Question

a student was asked to find9/17 of a number but he made a mistake of finding 9/7of it the answer is 90 more than the correct answer find the answer​

Answer 1

Answer:

the number is 171.

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  

= (7x)/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