Question

The tens digit of a 2 digit number is twice its units digit .if the sum of the digits is 12 find the number

Answer 1

Answer:

let on unit place be x

let on tens place be y

according to first condition,

y=2x

2x-y= 0....(1)

according to second condition,

x+y=12....(2)

adding 1 and 2

3x=12

x=4

substituting x=4 in equation 2

x+y=12

4+y=12

y=12-4

y=8

therefore two digit no.= 10y+x

10×8+4

84