Question

Use the Rule of 72 to estimate how long it will take for India, Spain, and South Africa to double their standards of living.

Short answer

The formula used to compute the approximate time by rule 72 is as follows :

$\text{Estimate Time}=\frac{72}{\text{GDP per capita growth}}$

Step-by-step solution

Concept introduction 

The rule 72 may be a concept which supplies how to get an estimation of approximate time within which the standards i.e. income are often doubled of a rustic.

Explanation of Solution

The data provided below is taken from the link of The World Bank database in respect to India, Spain, and South Africa: