Original practice · fully worked
Original variant: annual arithmetic increment supported by a fixed perpetuity price
An annual perpetuity-immediate is priced at 25,000 using a 4% annual effective yield. Its first payment is 500, and every later payment exceeds the preceding payment by K. Calculate K.
- A
18.00 - B
19.00 - C
20.00 - D
21.00 - E
22.00
Answer and calculation
The 500 level component is worth 12,500. The remaining 12,500 equals K divided by 4% squared, giving annual increment 20.00, choice C.
Setup
Setup
Write the arithmetic perpetuity as a level-payment part plus an increasing part.
25000=0.04500+(0.04)2K Model
Model
Remove the level component and multiply the residual price by the square of the yield.
K=(0.04)2(25000−0.04500) Compute
Compute
The resulting annual increment is 20.0000.
K=20.00000000 Answer
Answer
Each payment increases by 20.00, selecting choice C.
K=20.00(C)