Question

What annual growth rate is needed for a country to double its output in each of the following cases? Instructions: In parts a-c, enter your answers as whole numbers. In part d, round your answer to 1 decimal place.
a. In 7 years: 10percent
b. In 35 years: 2percent.
c. In 70 years: 1percent
d. In 140 years: 0.5percent.

Answer 1

Answer:

A. 10%

B. 2%

C. 1%

D. 0.5%

Explanation:

Using the rule of 70, which is a method for estimating an investment's doubling time. It is a way to know how quickly something will double when it's growing exponentially. Just divide 70 by the percent increase, and you get the doubling time.

Years to double = 70 ÷ Growth Rate

Therefore, getting the Growth rate; rearrange the equation

Growth Rate = 70 ÷ Years to Double.

A. In 7 years = 70÷7 = 10%

B. In 35 years = 70÷35 = 2%

C. In 70 years = 70 ÷ 70 = 1%

D. In 140 years = 70 ÷ 140 = 0.5%