Question

Question 9

9) ** The sum of the digits of a certain two-digit number is 7. Reversingits agits decreases the
number by 63. Find the number.
The number is

Answer 1

The required number is 70.

Explanation:

let the no. be 10y + x where x is unit digit and y is ten's digit.

given , sum of the digit is 7

x + y = 7 ...(1)

also , reversing the no. we get 10x + y ,where x is ten's digit and y is unit digit.

given reversed digit decreases the number by 63 .

so, 10y + x - ( 10x + y ) = 63

9y -9x = 63

( dividing both side by 9 )

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

adding 1 and 2 [ refer attachment ]

so the required original number is

10y + x = 10×7+0 = 70