Question

In a two digit number the units digiy is twice the tens digit . if 27 is added to the no the digits interchange their places . find the no

Answer 1

Let the digits be x and y

Then the two-digit number is 10x + y

Given : y = 2x ----------1

Now 27 added to the no

10x + y + 27 = 10y + x

9y – 9x = 27

y – x = 3 -----------2

Substitute the value of y in eqn 2

2x – x = 3

x = 3

and y = 2 * 3 = 6

Therefore the no is 10x + y = 10 * 3 + 6 = 36

Answer : The two digit no is 36.

Answer 2

Step-by-step explanation:

Let

The unit digit=x

TheTen digit=y

number=10y+x

A. to.q

1 case: x=2y. _ (1)

2 case: 10y+x+27= 10x+y

9x-9y=27

x-y=3. _ (2)

putting the value of x in equation (2)

(2y)-y=3

(y=3)

putting the value of y in equation (1)

x=2(3)

(X=6)

number=10y+x

=10(3)+6

=30+6

=36