This Exam FM sample reference tests Loan Balances and Amortization. The 3% level-payment option totals 1344.31. Under constant principal, interest is i times the sum of balances 1,000 through 50, totaling 10500. Equating totals gives i = 3.28%, choice C.
These notes identify the calculation error associated with each wrong letter when that error is reproducible.
AChoice A (2.86%) does not satisfy the equality of total payments under the level-payment and constant-principal schedules; no distinct standard one-step error is identifiable.
BChoice B (3.00%) does not satisfy the equality of total payments under the level-payment and constant-principal schedules; no distinct standard one-step error is identifiable.
DChoice D (3.44%) does not satisfy the equality of total payments under the level-payment and constant-principal schedules; no distinct standard one-step error is identifiable.
EChoice E (4.76%) does not satisfy the equality of total payments under the level-payment and constant-principal schedules; no distinct standard one-step error is identifiable.
Original practice · fully worked
Original variant: total-payment penalty of a higher-rate constant-principal schedule
A 12,000 loan can be repaid over ten years either by level annual payments at 4% or by 1,200 principal each year plus 5% interest on the opening balance. Calculate how much larger the total payments are under the constant-principal option.
A 404.07
B 429.32
C 454.58
D 479.83
E 505.09
Variant answer in brief
The 4% level-payment schedule totals 14,794.91. Principal plus 5% interest on the ten opening balances totals 15,300.00, an excess of 505.09, choice E.
Setup
Setup
Compute the annual level payment and ten-payment total under option A.
R=a10∣0.0412000
TA=10R
Model
Model
Under option B, add 12,000 principal to 5% of the ten opening balances.
TB=12000+0.05k=0∑9(12000−1200k)
Compute
Compute
The totals are 14794.91 and 15300.00, so the excess is 505.09.
TB−TA=505.08668038
Answer
Answer
The constant-principal option costs 505.09 more, selecting choice E.
The 2210-page Financial Mathematics Proof Manual reorganizes 461 verified Exam FM solutions by syllabus skill and adds formula proofs, error patterns, and original worked practice.