Question

A number is multiplied by 7/5 what percentage increase it​

Answer 1

Answer:

Then(x+7)×5=45

(x+7)×5=45

x+7=9

x= 9-7

Answer 2

Ans. Let us assume no. = 15

Correct answer would be= 15× 4/3 = 20

Incorrect answer is = 15 × 7/5 = 21

Difference in two answers is = 21–20 = 1

Now apply unitary method

If no. is 15 the difference is = 1

If no. is 1 the difference is = 1/15

If no. is 100 the difference is =( 1/15) ×100 = 20/3

Ans = 20/3 = 6.67 %

Note We can assume any number the answer will be same.