This Exam FM sample reference tests Geometrically Increasing Loan Payments. The initial payment is 2584.39 from the ten-payment growing-annuity loan equation. After payment 8 only payments 9 and 10 remain; their value at time 8 is 7353.15, choice C.
These notes identify the calculation error associated with each wrong letter when that error is reproducible.
AChoice A values the ninth payment but omits part of the tenth payment from the post-eighth-payment balance.
BChoice B grows the first payment seven times for payment 9 instead of eight times.
DChoice D places the balance immediately before payment 8 and therefore includes an extra scheduled payment.
EChoice E discounts the last two payments at 6%, the payment-growth rate, rather than the 10% loan rate.
Original practice · fully worked
Original variant: principal supported by declining payments
A borrower promises eight annual payments, beginning with 3,000 at the end of year 1. Each later payment is 3% smaller than the preceding one. At a 5% annual effective loan rate, determine the original principal advanced.
A 15,984.22
B 16,705.90
C 17,190.41
D 17,607.44
E 18,442.08
Variant answer in brief
Discounting the eight payments 3000 times 0.97 to successive powers at 5% gives an original principal of 17607.44, choice D.
Setup
Setup
Payment k equals 3000 times 0.97 to the k minus one.
Ck=3,000(0.97)k−1
Model
Model
The principal is the present value of all eight promised payments.
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.