The ratio of the two natural numbers is 5 : 6. If a certain number is added to both the numbers, the ratio becomes 7 : 8. If the larger number exceeds the smaller number by 10, find the number added?
A). 5
B). 10
C). 20
D). 30
20
Let the two numbers be 5x and 6x.
Let the numbers added to both so that their ratio becomes 7 : 8 be k.
(5x + k) / (6x + k) = 7/8
=> 40x + 8k = 42x + 7k => k = 2x.
6x - 5x = 10 => x = 10
k = 2x = 20.