Question

In a 2 digit no. The units digit is 4 times the tens digit and the sum of the digit is 10 find the number

Answer 1

Let the unit digit be x and tens digit be y. So,
x = 4y ........................(1)
and
x+y =10 ........................(2)
Substituting x= 4y in eqution (2) gives
4y +y = 10
or, 5y = 10
or, y = 2
So, x = 4y = 4 X 2 = 8
Hence, the number is 28. Ans.