The population of a new city is 5 million and is growing at $20 \%$ annually. How many years would it take to double at this growth rate?
(A) 3-4 years
(B) $4-5$ years
(C) 5 -6 years
(D) $6-7$ years
The population of a new city is 5 million and is growing at $20 \%$ annually. How many years would it take to double at this growth rate?
(A) 3-4 years
(B) $4-5$ years
(C) 5 -6 years
(D) $6-7$ years