Question

in a two digit number digit on the ten place is twice the digit at the units place if the number obtained by interchanging the digit is added to the original number the sum is 66 find the number

Answer 1

Let the tens digit be x and the units digit be y.

So the number=10x+y

A.q.

=>x=2y(equation 1)

After interchanging the digits we get

10y+x

Also,

=>(10x+y)+(10y+x)=66

=>10x+y+10y+x=66

=>11y+11x=66

=>11(y+x)=66

=>y+x=66/11

=>y+x=6

Frim equation 1 x=2y

So, y+2y=6

=>3y=6

=>y=6/3

=>y=2

And x=2(2)=4

Hence the number is 42.