Question

A number consists of two digits whose sum is 9.If 9 is subtracted from the number ,its digits are interchanged. Find the numbers.

Answer 1

Let the ones place digit be b
And tens place digit be a

No. = 10a +b
Reversed no. = 10b +a

According to question
a+b = 9 ------(1)

10a+b-9 = 10b+ a
=> 9a - 9b = 9
=> a - b= 1 -------(2)

On adding equation 1 and 2, we get
2a = 10
a= 5
b = 4

Required no. = 54