Question

If the population of Town B is 50% greater than the population of Town A and the populations of Town C is 20% greater than the population of Town A, then what percent greater is the population of Town B tan the population of Town C

Answer 1

Let
A = population of town A,
B = population of town B,
C = population of town C.

Because the population of town B is 50% greater than that of town A,
B = 1.5A                    (1)

Because the population of town C is 20% greater than that of town A,
C = 1.2A                  (2)

From (1), obtain
A = B/1.5 = (2/3)B        (3)

Substitute (3) into (2).
C = 1.2*(2/3)*B = 0.8B
Divide each side by 0.8.
1.25C = B
This result means that B is 25% greater than C.

Answer: 25%