Non-Annual Compounding
Engineering Economics · FE Reference Handbook section
Core formulas for this FE topic
Definitions, applicability, units, assumptions and worked examples for each relation.
Worked exam-style examples
The four ways this section is written on the real exam — thoughts first, then equations, then substitution.
A engineering economics problem uses Uniform-series present worth. Given annual amount (A) = 48,300 $/yr; interest rate (i) = 0.0250 1/yr; years (n) = 25.0000 yr, determine the present worth (P) in $.
Given
annual amount (A) = 48,300 $/yr
Find
present worth (P), in $
Start with the thinking
- The governing relation printed in this handbook section is Uniform-series present worth.
- Everything except P is given, so isolate P symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Engineering Economics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that P stands alone on the left-hand side.
Step 3 — List the givens: annual amount (A) = 48,300 $/yr, interest rate (i) = 0.0250 1/yr, years (n) = 25.0000 yr.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning P = 889,897 $ to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 1,779,795 — kept a factor of two that cancels in the correct rearrangement.
- 444,949 — dropped that same factor in the other direction.
- 978,887 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Engineering Economics → Non-Annual Compounding
A engineering economics problem uses Uniform-series present worth. Given interest rate (i) = 0.0550 1/yr; years (n) = 7.0000 yr; present worth (P) = 316,023 $, determine the annual amount (A) in $/yr.
Given
present worth (P) = 316,023 $
Find
annual amount (A), in $/yr
Start with the thinking
- The governing relation printed in this handbook section is Uniform-series present worth.
- Everything except A is given, so isolate A symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Engineering Economics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that A stands alone on the left-hand side.
Step 3 — List the givens: interest rate (i) = 0.0550 1/yr, years (n) = 7.0000 yr, present worth (P) = 316,023 $.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning A = 55,609 $/yr to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 111,218 — kept a factor of two that cancels in the correct rearrangement.
- 27,804 — dropped that same factor in the other direction.
- 61,170 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Engineering Economics → Non-Annual Compounding
A engineering economics problem uses Uniform-series present worth. Given annual amount (A) = 47,700 $/yr; interest rate (i) = 0.0750 1/yr; years (n) = 25.0000 yr, determine the present worth (P) in $.
Given
annual amount (A) = 47,700 $/yr
Find
present worth (P), in $
Start with the thinking
- The governing relation printed in this handbook section is Uniform-series present worth.
- Everything except P is given, so isolate P symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Engineering Economics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that P stands alone on the left-hand side.
Step 3 — List the givens: annual amount (A) = 47,700 $/yr, interest rate (i) = 0.0750 1/yr, years (n) = 25.0000 yr.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning P = 531,709 $ to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 1,063,419 — kept a factor of two that cancels in the correct rearrangement.
- 265,855 — dropped that same factor in the other direction.
- 584,880 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Engineering Economics → Non-Annual Compounding
A engineering economics problem uses Uniform-series present worth. Given interest rate (i) = 0.1000 1/yr; years (n) = 29.0000 yr; present worth (P) = 461,833 $, determine the annual amount (A) in $/yr.
Given
present worth (P) = 461,833 $
Find
annual amount (A), in $/yr
Start with the thinking
- The governing relation printed in this handbook section is Uniform-series present worth.
- Everything except A is given, so isolate A symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Engineering Economics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that A stands alone on the left-hand side.
Step 3 — List the givens: interest rate (i) = 0.1000 1/yr, years (n) = 29.0000 yr, present worth (P) = 461,833 $.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning A = 49,291 $/yr to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 98,581 — kept a factor of two that cancels in the correct rearrangement.
- 24,645 — dropped that same factor in the other direction.
- 54,220 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Engineering Economics → Non-Annual Compounding
A engineering economics problem uses Uniform-series present worth. Given annual amount (A) = 41,800 $/yr; interest rate (i) = 0.0300 1/yr; years (n) = 17.0000 yr, determine the present worth (P) in $.
Given
annual amount (A) = 41,800 $/yr
Find
present worth (P), in $
Start with the thinking
- The governing relation printed in this handbook section is Uniform-series present worth.
- Everything except P is given, so isolate P symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Engineering Economics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that P stands alone on the left-hand side.
Step 3 — List the givens: annual amount (A) = 41,800 $/yr, interest rate (i) = 0.0300 1/yr, years (n) = 17.0000 yr.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning P = 550,344 $ to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 1,100,688 — kept a factor of two that cancels in the correct rearrangement.
- 275,172 — dropped that same factor in the other direction.
- 605,378 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Engineering Economics → Non-Annual Compounding
A engineering economics problem uses Uniform-series present worth. Given interest rate (i) = 0.0750 1/yr; years (n) = 23.0000 yr; present worth (P) = 102,243 $, determine the annual amount (A) in $/yr.
Given
present worth (P) = 102,243 $
Find
annual amount (A), in $/yr
Start with the thinking
- The governing relation printed in this handbook section is Uniform-series present worth.
- Everything except A is given, so isolate A symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Engineering Economics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that A stands alone on the left-hand side.
Step 3 — List the givens: interest rate (i) = 0.0750 1/yr, years (n) = 23.0000 yr, present worth (P) = 102,243 $.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning A = 9,461 $/yr to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 18,922 — kept a factor of two that cancels in the correct rearrangement.
- 4,731 — dropped that same factor in the other direction.
- 10,407 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Engineering Economics → Non-Annual Compounding
A engineering economics problem uses Uniform-series present worth. Given annual amount (A) = 3,100 $/yr; interest rate (i) = 0.1000 1/yr; years (n) = 23.0000 yr, determine the present worth (P) in $.
Given
annual amount (A) = 3,100 $/yr
Find
present worth (P), in $
Start with the thinking
- The governing relation printed in this handbook section is Uniform-series present worth.
- Everything except P is given, so isolate P symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Engineering Economics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that P stands alone on the left-hand side.
Step 3 — List the givens: annual amount (A) = 3,100 $/yr, interest rate (i) = 0.1000 1/yr, years (n) = 23.0000 yr.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning P = 27,538 $ to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 55,076 — kept a factor of two that cancels in the correct rearrangement.
- 13,769 — dropped that same factor in the other direction.
- 30,292 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Engineering Economics → Non-Annual Compounding
A engineering economics problem uses Uniform-series present worth. Given interest rate (i) = 0.0450 1/yr; years (n) = 10.0000 yr; present worth (P) = 478,105 $, determine the annual amount (A) in $/yr.
Given
present worth (P) = 478,105 $
Find
annual amount (A), in $/yr
Start with the thinking
- The governing relation printed in this handbook section is Uniform-series present worth.
- Everything except A is given, so isolate A symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Engineering Economics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that A stands alone on the left-hand side.
Step 3 — List the givens: interest rate (i) = 0.0450 1/yr, years (n) = 10.0000 yr, present worth (P) = 478,105 $.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning A = 60,422 $/yr to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 120,845 — kept a factor of two that cancels in the correct rearrangement.
- 30,211 — dropped that same factor in the other direction.
- 66,465 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Engineering Economics → Non-Annual Compounding
A engineering economics problem uses Uniform-series present worth. Given annual amount (A) = 44,500 $/yr; interest rate (i) = 0.1150 1/yr; years (n) = 11.0000 yr, determine the present worth (P) in $.
Given
annual amount (A) = 44,500 $/yr
Find
present worth (P), in $
Start with the thinking
- The governing relation printed in this handbook section is Uniform-series present worth.
- Everything except P is given, so isolate P symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Engineering Economics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that P stands alone on the left-hand side.
Step 3 — List the givens: annual amount (A) = 44,500 $/yr, interest rate (i) = 0.1150 1/yr, years (n) = 11.0000 yr.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning P = 270,104 $ to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 540,208 — kept a factor of two that cancels in the correct rearrangement.
- 135,052 — dropped that same factor in the other direction.
- 297,114 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Engineering Economics → Non-Annual Compounding
A engineering economics problem uses Uniform-series present worth. Given interest rate (i) = 0.0550 1/yr; years (n) = 16.0000 yr; present worth (P) = 259,390 $, determine the annual amount (A) in $/yr.
Given
present worth (P) = 259,390 $
Find
annual amount (A), in $/yr
Start with the thinking
- The governing relation printed in this handbook section is Uniform-series present worth.
- Everything except A is given, so isolate A symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Engineering Economics items reward recognising the unknown before touching a calculator.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that A stands alone on the left-hand side.
Step 3 — List the givens: interest rate (i) = 0.0550 1/yr, years (n) = 16.0000 yr, present worth (P) = 259,390 $.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning A = 24,793 $/yr to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 49,586 — kept a factor of two that cancels in the correct rearrangement.
- 12,397 — dropped that same factor in the other direction.
- 27,272 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Engineering Economics → Non-Annual Compounding