The ratio of two numbers A and B is 7 : 5. If both numbers are increased by 4, then the ratio of A and B becomes 4 : 3. What is the initial value of B?
Show answer & explanation
Correct answer: A
Explanation
Let A = 7x
B = 5x
(7x + 4)/(5x + 4) = 4/3
3(7x + 4) = 4(5x + 4)
21x + 12 = 20x + 16
x = 4
B = 5x = 5 × 4 = 20