Question

A student was asked to find 7/19 of a certain number.He made the mistake of finding 7/9 of it.His answer was 70more than the correct number.Find the number.

Answer 1

Solution :-

Let the required number be x

⇒ 7/19th of the number = (7*x)/19

= 7x/19

Wrong calculation done by the student, which is 70 more than the correct number = (7/9th of x) - 70

= (7*x)/9 - 70

= 7x/9 - 70

Now, according to the question.

⇒ 7x/19 = 7x/9 - 70/1

⇒ 7x/19 = (7x - 630)/9

⇒ 63x = 133x - 11970

⇒ 63x - 133x = - 11970

⇒ - 70x = - 11970

⇒ 70x = 11970

⇒ x = 11970/70

⇒ x = 171

So, the number is 171.

Answer.

Answer 2

A student was asked to find 7/19 of a certain number.He made the mistake of finding 7/9 of it.His answer was 70more than the correct number.Find the number. answer is 171