This Exam FM sample reference tests Annuities. At year 15, the first deposit has 14 years of 8% growth and each later deposit has one fewer. Summing the growing deposits produces factor 32.284034, so X = 61.95, choice C.
These notes identify the calculation error associated with each wrong letter when that error is reproducible.
AChoice A (45) does not satisfy the time-15 sum of all fifteen growing deposits at their actual accumulation periods; no distinct standard one-step error is identifiable.
BChoice B (57) does not satisfy the time-15 sum of all fifteen growing deposits at their actual accumulation periods; no distinct standard one-step error is identifiable.
DChoice D (67) does not satisfy the time-15 sum of all fifteen growing deposits at their actual accumulation periods; no distinct standard one-step error is identifiable.
EChoice E (88) does not satisfy the time-15 sum of all fifteen growing deposits at their actual accumulation periods; no distinct standard one-step error is identifiable.
Original practice · fully worked
Original variant: deposit growth rate inferred from a terminal fund
A saver deposits 100 at year 1 and makes nine further year-end deposits, each growing by the same rate g. The account earns 6% annually. The fund immediately after the year-10 deposit is 1429.63. Calculate g.
A 1.60%
B 1.70%
C 1.80%
D 1.90%
E 2.00%
Variant answer in brief
Equating the ten accumulated deposits to the quoted year-10 fund and solving the geometric sum gives growth rate 2.00%, choice E.
Setup
Setup
Write deposit k and its accumulation to year 10.
Dk=100(1+g)k−1
F10=k=1∑10Dk(1.06)10−k
Model
Model
Set that finite sum equal to the quoted terminal fund.
1429.63=100k=1∑10(1+g)k−1(1.06)10−k
Compute
Compute
The relevant root is g = 2.000000%.
g=0.0200000000
Answer
Answer
The annual deposit growth rate is 2.00%, selecting choice E.
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