Original practice · fully worked
Original variant: sum of two yields satisfying one nonconventional value equation
The present value of 8,550 now plus 10,000 at year 2 equals the present value of 18,500 at year 1 at two positive annual effective rates. Calculate the sum of those two rates.
- A
15.56% - B
16.37% - C
17.19% - D
18.01% - E
18.83%
Answer and calculation
The value equation factors into discount roots 0.95 and 0.90. These correspond to rates 5.26% and 11.11%, whose sum is 16.37%, choice B.
Setup
Setup
Write the equality as a quadratic in the annual discount factor.
8550+10000v2=18500v Model
Model
Factor the quadratic to obtain both positive discount roots.
10000(v−0.95)(v−0.90)=0 Compute
Compute
The corresponding rates are 5.263158% and 11.111111%, summing to 16.374269%.
i1=1/0.95−1 i2=1/0.90−1 Answer
Answer
The sum of the two rates is 16.37%, selecting choice B.
i1+i2≈16.37%(B)