This Exam FM sample reference tests Annuities and Perpetuities. On a half-year scale the immediate perpetuity-due value is 1 + 1/j = 23, so j = 1/22; compounding that half-year rate twice gives annual effective rate 9.3%, choice E.
These notes identify the calculation error associated with each wrong letter when that error is reproducible.
AChoice A is inconsistent with the half-year perpetuity-due value and annual conversion; no distinct standard single-step error producing it is identifiable.
BChoice B is inconsistent with the half-year perpetuity-due value and annual conversion; no distinct standard single-step error producing it is identifiable.
CChoice C is inconsistent with the half-year perpetuity-due value and annual conversion; no distinct standard single-step error producing it is identifiable.
DChoice D is inconsistent with the half-year perpetuity-due value and annual conversion; no distinct standard single-step error producing it is identifiable.
Original practice · fully worked
Original variant: semiannual perpetuity value from an annual rate
Payments of 1 occur every six months forever, beginning immediately. The annual effective interest rate is 10.25%. Determine the present value.
A 19
B 20
C 21
D 22
E 23
Variant answer in brief
The equivalent half-year rate is 5%, so the semiannual perpetuity-due value is 21, choice C.
Setup
Setup
Convert the annual effective accumulation factor to one half-year.
1+j=1.1025=1.05
Model
Model
The square root gives a 5% effective rate per payment period.
j=0.05
Compute
Compute
An immediate first payment makes the perpetuity value one plus one over the rate.
PV=1+0.051=21
Answer
Answer
The present value is 21, corresponding to choice C.
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