Question

In a two digit number , digits in unit place is twice the digit in tens place . if 27 is added to it ,digits are reserved. find the number.

Answer 1

Let us assume, x is a tenth place digit and y is the unit place digit of a two-digit number.

Therefore, the two-digit number = 10x + y and the reversed number = 10y + x

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

Also given:
10x + y + 27 = 10y + x
9y - 9x = 27
y - x = 3

Substitute the value of y from equation 1 in equation 2

2x - x = 3
x = 3

Therefore y = 2x = 2 * 3 = 6

Therefore, the two-digit number = 10x + y = 10*3 + 6 = 36

Answer 2

Answer:36

Step-by-step explanation

Let the number in tens place be x

So,

Number = x 2x

= x×10 +x ( eg. 56 = 5×10 + 6 )

Their reverse order = 2x × 10 + ×

If we add 27 then only it becomes reverse = x×10 + 2x + 27 = 2x× 10 + x

= 10x + 2x +27=20x+x

=12x+27=21x

=27 =21x - 12x

= 27 = 9x

x= 27÷9

x = 3

Original number = x 2x

3 2×3 = 36

Checking = 36 + 27 = 63 (reverse of 36)