This Exam FM sample reference tests Annuities and Perpetuities. Company Q accumulates to 84.7009X; Company R's principal and separately reinvested interest total 7,911.91, so X = 93.41, choice D.
These notes identify the calculation error associated with each wrong letter when that error is reproducible.
AChoice A is inconsistent with the principal-plus-reinvested-interest decomposition; no distinct standard single-step error producing it is identifiable.
BChoice B is inconsistent with the principal-plus-reinvested-interest decomposition; no distinct standard single-step error producing it is identifiable.
CChoice C is inconsistent with the principal-plus-reinvested-interest decomposition; no distinct standard single-step error producing it is identifiable.
EChoice E is inconsistent with the principal-plus-reinvested-interest decomposition; no distinct standard single-step error producing it is identifiable.
Original practice · fully worked
Original variant: principal and separately reinvested library interest
A library deposits 100 at the beginning of each year for ten years. Principal remains uncredited, but at each year-end the accumulated principal earns 5%; that interest is moved to a separate account earning 3% until year 10. Find total value at year 10.
A 1,200.00
B 1,250.00
C 1,301.30
D 1,350.00
E 1,400.00
Variant answer in brief
Principal totals 1,000 and the ten interest transfers accumulate to 301.30, giving 1,301.30, choice C.
Setup
Setup
At year k the source principal is 100k, so its transferred interest is 5k.
VP=10(100)=1000
Model
Model
Each interest transfer then grows in the separate 3% account for the remaining years.
VI=k=1∑105k(1.03)10−k=301.2993
Compute
Compute
Those transfers accumulate to 301.2993, while principal itself totals 1,000.
V=1000+301.2993=1301.2993
Answer
Answer
The combined year-ten value is 1,301.30, corresponding to choice C.
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