Indices
Construction Engineering · 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 construction engineering problem uses Crew productivity. Given production rate (P) = 9.0000 units/hr; duration (t) = 159.0 hr, determine the total quantity (Q) in units.
Given
Find
total quantity (Q), in units
Start with the thinking
- The governing relation printed in this handbook section is Crew productivity.
- Everything except Q is given, so isolate Q 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.
- Construction Engineering 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 Q stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning Q = 1,431 units to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 2,862 — kept a factor of two that cancels in the correct rearrangement.
- 715.5 — dropped that same factor in the other direction.
- 1,574 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Construction Engineering → Indices
A construction engineering problem uses Total cost from unit cost. Given unit cost (cu) = 123.5 $/unit; quantity (Q) = 7,247 units, determine the total cost (C) in $.
Given
unit cost (cu) = 123.5 $/unit
Find
total cost (C), in $
Start with the thinking
- The governing relation printed in this handbook section is Total cost from unit cost.
- Everything except C is given, so isolate C 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.
- Construction Engineering 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 C stands alone on the left-hand side.
Step 3 — List the givens: unit cost (cu) = 123.5 $/unit, quantity (Q) = 7,247 units.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning C = 895,005 $ to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 1,790,009 — kept a factor of two that cancels in the correct rearrangement.
- 447,502 — dropped that same factor in the other direction.
- 984,505 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Construction Engineering → Indices
earned value cost performance index for a highway construction contract Given earned value (BCWP) (EV) = 29,000 $; actual cost (ACWP) (AC) = 85,000 $; cost variance (CV) = -100,000 $, determine the cost performance index (CPI).
Given
earned value (BCWP) (EV) = 29,000 $
actual cost (ACWP) (AC) = 85,000 $
cost variance (CV) = -100,000 $
Find
cost performance index (CPI)
Start with the thinking
- The governing relation printed in this handbook section is Earned value: cost performance index and cost variance.
- Everything except CPI is given, so isolate CPI 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.
- Earned value management measures project cost performance and productivity using cost performance index and cost variance.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that CPI stands alone on the left-hand side.
Step 3 — List the givens: earned value (BCWP) (EV) = 29,000 $, actual cost (ACWP) (AC) = 85,000 $, cost variance (CV) = -100,000 $.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning CPI = 0.3412 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.6824 — kept a factor of two that cancels in the correct rearrangement.
- 0.1706 — dropped that same factor in the other direction.
- 0.3753 — rounded an intermediate value before the final step.
Reference: FE Handbook — Nomenclature (earned value / productivity)
A construction engineering problem uses Crew productivity. Given duration (t) = 132.0 hr; total quantity (Q) = 223.0 units, determine the production rate (P) in units/hr.
Given
Find
production rate (P), in units/hr
Start with the thinking
- The governing relation printed in this handbook section is Crew productivity.
- 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.
- Construction Engineering 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
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning P = 1.6894 units/hr to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 3.3788 — kept a factor of two that cancels in the correct rearrangement.
- 0.8447 — dropped that same factor in the other direction.
- 1.8583 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Construction Engineering → Indices
A construction engineering problem uses Total cost from unit cost. Given quantity (Q) = 9,647 units; total cost (C) = 21,314 $, determine the unit cost (cu) in $/unit.
Given
total cost (C) = 21,314 $
Find
unit cost (cu), in $/unit
Start with the thinking
- The governing relation printed in this handbook section is Total cost from unit cost.
- Everything except cu is given, so isolate cu 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.
- Construction Engineering 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 cu stands alone on the left-hand side.
Step 3 — List the givens: quantity (Q) = 9,647 units, total cost (C) = 21,314 $.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning cu = 2.2094 $/unit to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 4.4188 — kept a factor of two that cancels in the correct rearrangement.
- 1.1047 — dropped that same factor in the other direction.
- 2.4303 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Construction Engineering → Indices
earned value analysis to assess cost performance on a construction project Given earned value (BCWP) (EV) = 174,500 $; actual cost (ACWP) (AC) = 398,500 $; cost performance index (CPI) = 0.8800, determine the cost variance (CV) in $.
Given
earned value (BCWP) (EV) = 174,500 $
actual cost (ACWP) (AC) = 398,500 $
Find
cost variance (CV), in $
Start with the thinking
- The governing relation printed in this handbook section is Earned value: cost performance index and cost variance.
- Everything except CV is given, so isolate CV 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.
- Earned value management measures project cost performance and productivity using cost performance index and cost variance.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that CV stands alone on the left-hand side.
Step 3 — List the givens: earned value (BCWP) (EV) = 174,500 $, actual cost (ACWP) (AC) = 398,500 $, cost performance index (CPI) = 0.8800.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning CV = -224,000 $ to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- -448,000 — kept a factor of two that cancels in the correct rearrangement.
- -112,000 — dropped that same factor in the other direction.
- -246,400 — rounded an intermediate value before the final step.
Reference: FE Handbook — Nomenclature (earned value / productivity)
A construction engineering problem uses Crew productivity. Given production rate (P) = 19.0000 units/hr; total quantity (Q) = 657.0 units, determine the duration (t) in hr.
Given
Find
duration (t), in hr
Start with the thinking
- The governing relation printed in this handbook section is Crew productivity.
- Everything except t is given, so isolate t 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.
- Construction Engineering 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 t stands alone on the left-hand side.
Step 3 — List the givens: production rate (P) = 19.0000 units/hr, total quantity (Q) = 657.0 units.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning t = 34.5789 hr to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 69.1579 — kept a factor of two that cancels in the correct rearrangement.
- 17.2895 — dropped that same factor in the other direction.
- 38.0368 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Construction Engineering → Indices
A construction engineering problem uses Total cost from unit cost. Given unit cost (cu) = 50.5000 $/unit; total cost (C) = 127,360 $, determine the quantity (Q) in units.
Given
unit cost (cu) = 50.5000 $/unit
total cost (C) = 127,360 $
Find
quantity (Q), in units
Start with the thinking
- The governing relation printed in this handbook section is Total cost from unit cost.
- Everything except Q is given, so isolate Q 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.
- Construction Engineering 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 Q stands alone on the left-hand side.
Step 3 — List the givens: unit cost (cu) = 50.5000 $/unit, total cost (C) = 127,360 $.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning Q = 2,522 units to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 5,044 — kept a factor of two that cancels in the correct rearrangement.
- 1,261 — dropped that same factor in the other direction.
- 2,774 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Construction Engineering → Indices
productivity and cost variance tracking on a building project schedule Given earned value (BCWP) (EV) = 160,000 $; cost performance index (CPI) = 0.5200; cost variance (CV) = 38,000 $, determine the actual cost (ACWP) (AC) in $.
Given
earned value (BCWP) (EV) = 160,000 $
cost variance (CV) = 38,000 $
Find
actual cost (ACWP) (AC), in $
Start with the thinking
- The governing relation printed in this handbook section is Earned value: cost performance index and cost variance.
- Everything except AC is given, so isolate AC 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.
- Earned value management measures project cost performance and productivity using cost performance index and cost variance.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that AC stands alone on the left-hand side.
Step 3 — List the givens: earned value (BCWP) (EV) = 160,000 $, cost performance index (CPI) = 0.5200, cost variance (CV) = 38,000 $.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning AC = 307,692 $ to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 615,385 — kept a factor of two that cancels in the correct rearrangement.
- 153,846 — dropped that same factor in the other direction.
- 338,462 — rounded an intermediate value before the final step.
Reference: FE Handbook — Nomenclature (earned value / productivity)
A construction engineering problem uses Crew productivity. Given production rate (P) = 18.0000 units/hr; duration (t) = 168.0 hr, determine the total quantity (Q) in units.
Given
Find
total quantity (Q), in units
Start with the thinking
- The governing relation printed in this handbook section is Crew productivity.
- Everything except Q is given, so isolate Q 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.
- Construction Engineering 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 Q stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning Q = 3,024 units to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 6,048 — kept a factor of two that cancels in the correct rearrangement.
- 1,512 — dropped that same factor in the other direction.
- 3,326 — rounded an intermediate value before the final step.
Reference: FE Reference Handbook — Construction Engineering → Indices