This Exam FM sample reference tests Annuities and Perpetuities. The nine-unit annual increases have present value 2,500, leaving 100 of value for the level P perpetuity; therefore P/0.06 = 100 and P = 6, choice B.
These notes identify the calculation error associated with each wrong letter when that error is reproducible.
AChoice A is inconsistent with the level-plus-arithmetic perpetuity decomposition; no distinct standard single-step error producing it is identifiable.
CChoice C is inconsistent with the level-plus-arithmetic perpetuity decomposition; no distinct standard single-step error producing it is identifiable.
DChoice D is inconsistent with the level-plus-arithmetic perpetuity decomposition; no distinct standard single-step error producing it is identifiable.
EChoice E is inconsistent with the level-plus-arithmetic perpetuity decomposition; no distinct standard single-step error producing it is identifiable.
Original practice · fully worked
Original variant: first payment in an increasing civic stipend
A civic stipend pays P after one year and then increases by 5 each year forever. At 8% effective annually, the stream is worth 1,800. Determine P.
A 70.00
B 75.00
C 81.50
D 90.00
E 100.00
Variant answer in brief
Removing the five-unit arithmetic increase value leaves a level perpetuity with P = 81.50, choice C.
Setup
Setup
Write the annual payment as a level P plus an increment of five times year index minus one.
1800=0.08P+0.0825
Model
Model
The delayed arithmetic increments have present value five divided by i squared.
0.08P=1800−781.25=1018.75
Compute
Compute
After removing 781.25 from the total value, the level perpetuity component is 1,018.75.
P=81.50
Answer
Answer
Multiplying by 8% gives first payment 81.50, choice C.
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