Twenty years ago,Dr.Montgomery borrowed money from her parents to pay her tuition at graduate school.Now she wants to pay them back.She gives them double what they gave her.According to the rule of 70,what interest rate would have given her parents the same amount of money if they had put it in the bank rather than lending it to their daughter?
A)3.5 percent
B)4.5 percent
C)5 percent
D)7 percent

Question

Quizplus · Accepted Answer

The rule of 70 is used to estimate the number of years it takes for an investment to double at a given interest rate. It states that you divide 70 by the annual interest rate to get the doubling time. Here, the doubling time is 20 years, so 70/20 = 3.5 percent.

Twenty Years Ago,Dr