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:

29

Step-by-step explanation:

(Let x be tens digit, y be units digit)

10x + y + 10y + x = 121  =>  11x + 11y = 121 ... (1)

y = x + 7 ... (2)

(1) divided by 11 ... x + y = 11 ... (3)

(2)                      ... -x + y = 7

(3) + (2)                   0 + 2y = 18

Therefore, y = 18/2 = 9

y = x + 7

Therefore, x = y -7

Therefore, x = 9-7 = 2

Hence, number is 29