This Exam FM sample reference tests Annuities. Value the first ten level payments of k, then at time 10 value a perpetuity beginning with k + 200 and increasing by 200 annually. Solving the linear 50,000 price equation gives k = 162.83, so choice C is correct.
These notes identify the calculation error associated with each wrong letter when that error is reproducible.
AChoice A (34) does not satisfy the first ten level payments plus the deferred arithmetic-increasing perpetuity; no distinct standard one-step error is identifiable.
BChoice B (86) does not satisfy the first ten level payments plus the deferred arithmetic-increasing perpetuity; no distinct standard one-step error is identifiable.
DChoice D (283) does not satisfy the first ten level payments plus the deferred arithmetic-increasing perpetuity; no distinct standard one-step error is identifiable.
EChoice E (409) does not satisfy the first ten level payments plus the deferred arithmetic-increasing perpetuity; no distinct standard one-step error is identifiable.
Original practice · fully worked
Original variant: perpetual annual increment inferred after an initial level block
A perpetuity-immediate pays 500 in each of years 1 through 8. Beginning with year 9, every payment is D larger than the previous payment. At a 6% annual yield, the price is 17570.24. Calculate D.
A 42.50
B 45.00
C 47.50
D 50.00
E 52.50
Variant answer in brief
Value the first eight payments separately and express the time-8 increasing perpetuity in terms of D. Solving the quoted price gives annual increment 50.00, choice D.
Setup
Setup
Value the first eight level payments at 6%.
PV1=500a8∣0.06
Model
Model
At time 8, the tail begins with 500 + D and increases by D forever.
PV8=0.06500+D+(0.06)2D
Compute
Compute
Solving the quoted price equation gives D = 50.000000.
17570.24=PV1+PV8(1.06)−8
D=50.00000000
Answer
Answer
The perpetual annual increment is 50.00, selecting choice D.
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