Sixty-five percent of a number is 42 less than four-fifth of that number. What is the number?

Question: Sixty-five percent of a number is 42 less than four-fifth of that number. What is the number?

Solution:
Let, the number = x.

ATQ,
65% of x = (4/5) of x - 42
⇒ 65x/100 = (4x/5) - 42
⇒ 13x/20 = (4x/5) - 42
⇒ (4x/5) - (13x/20) = 42
⇒ (16x - 13x)/20 = 42
⇒ 3x/20 = 42
⇒ 3x = 840
⇒ x = 840/3
∴ x = 280

So, the number is 280