Question

The digit in the tens place of a two-digit number is four times the digit in the units place. When the digits are reversed, the number obtained is 27 less than the original numbers. Find the original number.

Answer 1

Let the digit's in tens place be x

and digit in units place be y

Hence the original number will be xy=10×x+y

Given that x=4y

Then the reversed number will be yx=10×y+x
Given:

10y+x=10x+y−27
9x=9y+27
x=y+3
4y=y+3 [ ∵ x=4y ]
3y=3
y=1

and x=4(1)=4

∴ The original number =10x+y = 10(4)+1 = 40+1 = 41