Answer:
A
Step-by-step explanation:
Growth rate is defined as the level at which a variable grow over a period of time .
Workings
Applying rule 70
First country growth = 2%
T= 70/2 =35
Second country growth rate is 5%
T= 70/5
=14
If the first country doubles at 35 years and the second at 14 years,
How much sooner = the difference between the time it takes the two countries to double their GDP.
=35-14 = 21 years