Two numbers are such that the ratio between them is 3 : 5. If each is increased by 10, the ratio between the new numbers so formed is 5:7. Find the original numbers.
Let the numbers be 3x and 5x
According to the question
By cross multiplication
⇒ 7(3x + 10) = 5(5x + 10)
⇒ 21x + 70 = 25x + 50
⇒ 4x = 20
⇒ x = 5
So the numbers are 3x = 3 × 5 = 15 and 5x = 5 × 5 = 25