Question

The number consists of two digit. The digit at the tens place is twice that of the digit at the units place. if 18 is subtracted from the number,the digits are reversed . find the number.

Answer 1

Let the digit at unit's place be x. So, the digit at the tens place is 2x

the number is 10(2x)+x--------------------------------(1)

10(2x)+x-18=10(x)+2x

21x-18=12x

21x-12x=18

9x=18

x=2

2x=4

putting values in (1) we get

10(4)+2=42

So the number is 42