Question

In a two-digit number, the digit at the units place is 1 less than twice the digit at the tens place. If the places of both digits are interchanged, the new number formed is 27 more than the original number. The original number is

Answer 1

Let the unit place digit be y

and tens place digit be x

The number is 10x+y

Also y=2x-1..... (i)

According to question,

10y+x=(10x+y)+27...... (ii)

Putting (i) on (ii)

10(2x-1)+x=10x+2x-1+27

20x-10+x=12x+26

21x-12x=26+10

9x=36

x=4

Therefore, the number is 10(4)+{2(4)-1}=40+7=47