Question

A number consists of 2 digits.Sum of its digits is 15. If the place of digits are interchanged, then the number so obtained is 9 less than the original number. Find the original number.

Answer 1

Step-by-step explanation:

let tens place be x

and unit place be y

original number =10x+y

therefore x+y=15 .........i)

if the digit place is reversed

then equation will be

10y+x=(10x-y) -9

10y+y+x-10x=-9

11y+9x=-9...........ii)

9x+9y=135......iii)

x+y=15........iv)

by elimination method

-2y=126

y=126/-2

y=-63

putting the value of y in equation I)

x-63=15

x=15+63

x=78