Suppose real GDP in Puerto Rico is $48 billion and its annual growth rate is 8%. Real GDP for Puerto Rico will double in 6 years. 7.5 years. 8 years. 8.75 years. an indeterminate amount of years with the information given.

Answer: 8.75 years

Explanation:

To solve this we can use the brilliant rule of 70 which posits in it's simplest form that an amount will double if we decide 70 by it's required rate.

For example if you want to know how long your 20 billion will take to double given a 15% rate you say,

= 70/15

= 4.67 years.

In that same light therefore, we can calculate for this question thus,

= 70/8

= 8.75 years.

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