# Suppose a third project will cost \$20,000 today and yield a return of \$2,500 a year indefinitely. What is the present value of the project? What is the present value if the interest rate increases...

Suppose a third project will cost \$20,000 today and yield a return of \$2,500 a year indefinitely. What is the present value of the project? What is the present value if the interest rate increases to 20%?

Seeing \$2500 a year is a perpetuity, as it continues indefinitely, assume the interest rate to be 8%.

gsenviro | Certified Educator

The present cost = \$20,000

The PV of scenario 1 = - 20,000 + 2500/(0.08) = \$11,250

For scenario 2, PV = -20,000 + 2500/(0.2) = -\$15,000

(using the formula for PV of a perpetuity, PV = C/r, where C is the annual return and r is the rate of interest).

So, in this case, scenario 2, with a higher interest rate is not a favorable outcome, i.e. an increase in interest rate will reduce the PV of the perpetuity.

gsenviro | Certified Educator

a correction on scenario 2, the calculations are wrong.

Correct calculations,:

Scenario 2: PV = -20,000 + 2500/(0.2) = -20,000 + 12500 = -\$7,500

The outcome is still unfavorable due to high interest rate.

gsenviro | Certified Educator

That is correct.

The PV of a perpetuity with interest rate of r is given as PV = C/r

where C is the yearly return.