Question

A 2 digit no is 4 times the sum of its digit .If 18 is added to number the digit are reversed.find the no​

Answer 1

Answer:

let the two digit number is 10x+y

ATQ

10x+y = 4 ( x+y)

10x + y = 4x + 4y

6x-3y = 0

or

2x - y = 0. ( equation 1 )

it is also given that sum of digits is 9

x+ y = 9. ( equation 2 )

adding equation 1 and 2

3x = 9

x= 3

putting the value of x in equation 1

we get

y = 6

put the value of x and y in 10x +y

36 is the answer

I hope you are satisfied by my answer

Answer 2

Given:-

• A two digit number is 4 times the Sum of its digits.
• If 18 is added to the number the digits are reversed.

To find:-

• Find the original number ?

Solutions:-

• Let the digit at unit's place be 'y' and the digit at ten's place be 'x'.

Number = 10x + y

A two digit number is 4 times the Sum of its digits

According to question:-

=> 10x + y = 4(x + y)

=> 10x + y = 4x + 4y

=> 10x - 4x = 4y - y

=> 6x = 3y

=> 2x = y ........(i).

If 18 is added to the number the digits are reversed

Number obtained by reversing the digits = 10y + x

Original number + 18 = Number obtained by reversing the digits

According to question:-

=> 10x + y + 18 = 10y + x

=> 10x - x + y - 10y = -18

=> 9x - 9y = -18

=> 9(x - y) = -18

=> x - y = -18/9

=> x - y = -2

Putting the value of 'y' from equation (i) in equation (ii).

=> x - y = -2

=> x - 2x = -2

=> x = -2

Putting the value of 'x' in equation (ii)

=> 2x = y

=> 2(-2) = y

=> -4 = y

=> y = -4

Now,

Number = 10x + y

=> 10(2) + 4

=> 20 + 4

• Number = 24

Hence, the original number is 24.