Question

a student was asked to multiply a given number by 4 by 5. by mistake he divided by 4 by 5. his answer was 36 more than the given number. find the number

Answer 1

Let the given number be x.

Multiply this number(x) by 4/5 = x * 4/5 => 4x/5

Divide this number (x) by 4/5 = x ÷ 4/5
=> x * 5/4 = 5x/4

A/q, the difference between these numbers is 36.

As, his answer was 36 more than the original answer.

So,

➡ ( 5x/4 ) - ( 4x/5 ) = 36

➡ The LCM of 4 & 5 is 20.

➡ ( 25x - 16x )/20 = 36

➡ 9x/20 = 36

➡ 9x = 36 * 20

➡ x = ( 36*20 )/9

➡ x = 80

Answer :-

That number is 80.

Hope it will help you !!

Answer 2

Answer:

The given number = -80

Step-by-step explanation:

Let the given number be x

Given:

x multiplied by 4/5 = 36+x/(4/5)

So,

x*4/5 = x/(4/5)+36

4x/5 = 5x/4+36

4x/5 = (5x+144)/4 [By finding the common denominator of 36 and 5x]

4*4x = 5(5x+144)

16x = 25x+720

25x-16x = -720[By using transpose method]

9x = -720

x = -720/9

x = -80

Hope It Helps...