This Exam FM sample reference tests Annuities. Payment k is 100 times 0.9 to the k−1 and earns 3% from its receipt date through year 20. Accumulating all twenty payments gives 1295.80, so the balance is 1,296 and choice D.
These notes identify the calculation error associated with each wrong letter when that error is reproducible.
AChoice A (696) does not satisfy the year-20 accumulated value of all twenty 10%-declining payments; no distinct standard one-step error is identifiable.
BChoice B (717) does not satisfy the year-20 accumulated value of all twenty 10%-declining payments; no distinct standard one-step error is identifiable.
CChoice C (739) does not satisfy the year-20 accumulated value of all twenty 10%-declining payments; no distinct standard one-step error is identifiable.
EChoice E (1335) does not satisfy the year-20 accumulated value of all twenty 10%-declining payments; no distinct standard one-step error is identifiable.
Original practice · fully worked
Original variant: first deposit required for a declining contribution target
A saver makes twelve year-end deposits. The first is P and every later deposit is 5% smaller. The account earns 4% annually. Immediately after the twelfth deposit, the fund must equal 10,000. Calculate P.
A 678.81
B 721.24
C 763.67
D 806.09
E 848.52
Variant answer in brief
Accumulating twelve unit-scaled deposits under 5% decline and 4% account growth gives factor 11.785246. Dividing 10,000 by this factor gives first deposit 848.52, choice E.
Setup
Setup
Express deposit k and its accumulation to the time-12 target.
Dk=P(0.95)k−1
F12=k=1∑12Dk(1.04)12−k
Model
Model
Factor out the unknown first deposit from the finite geometric sum.
10000=Pk=1∑12(0.95)k−1(1.04)12−k
Compute
Compute
The unit accumulation factor is 11.78524590, so P = 848.52.
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