Question

(iii) The sum of a two-digit number and the number obtained by
interchanging the digit is 121. The digit at the units place is 7
more than the digit at the tens place. Find the number.​

Answer 1

Answer:

let the digit at the unit place be x and

the digit at the ten's place y

the original number =10y +x

The number obtained by a changing the digits 10x+y

A. F. C

Two digit number +the number obtained by interchange the digit=121

10y +x+10x+y=121

11x+11y=121

x+y=11----------1

A.S.C

the digit at unit place =the digit at ten's place +7

x=y+7

x-y=7---------------2

Add equation 1 and 2

X+y=11

x-y=7

-------------------

2x=16

x=8

put x=8

x+y=11

8+y=11

11-8=y

y =3

The original number =10y+x=30+8=38

The original number is 38