Question

You have $100 you have $100 to invest. If you can earn 12% interest, about how long does it take for your $100 investment to grow to $200? Suppose the interest rate is just half that, at 6%. At half the interest rate, does it take twice as long to double your money? Why or why not? How long does it take

Answer 1

Answer:

8.33333 years ;

Yes, the time doubles.

Explanation:

Investment amount = principal = $100

Interest rate, r = 12%

Time taken for investment to grow to $200

Using the simple interest formula :

A = P(1 + rt) ; t = time taken ; A = final amount = $200

200 = 100(1 + 0.12t)

200 = 100 + 12t

200 - 100 = 12t

100 = 12t

t = 100 / 12

t = 8.333 years

Time taken, if rate, r = 6%

200 = 100(1 + 0.06t)

200 = 100 + 6t

200 - 100 = 6t

100 = 6t

t = 100 / 6

t = 16.6666 years