Question

the sum of digits of a 2 digit number is 8. when the digits are reversed, the new number is less than the earlier by 18. then units digit of no. is?

Answer 1

Step-by-step explanation:

Let the digits be x and y.

ATQ ,

x + y = 8.

_____________

Let Ten's digit be 10y

And Unit digit be x.

If the digits are reversed, then Ten's digit = 10x and Unit digit = y.

ATQ, the reversed number is 18 less than the original number.

Therefore we can conclude,

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

9y - 18 = 9x

9y - 9x = 18

y - x = 18/9

y - x = 2

_______________

x + y = 8

y - x = 2

Solving these eq.

Adding the eqs.

y + x = 8

y - x = 2

2y = 10

y = 5

______________

y - x = 2

5 - x = 2

x = 5-2

x = 3

_________

Unit digit of the number is 3.

Hope it helps.