Question

A two digit no. Is such that the digit is added is 12. When 9 is added to the no. , the digit interchange their places. Determine the no.

Answer 1

Answer:

Let the number's tens place to be x and ones place to be y.

then no. will be 10x+y

According to question- x+y=12(equation-1)

and 10x+y+9=10y+x(no.resrved)

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

=> 9x-9y=-9

=>9(x-y)=-9

=> x-y=-1(equation 2)

Now putting the value of equation 1 and equation 2 together.

=x+y=12

=x-y=-1

=2x=11