Question

Sum of the digit of a number of two digit is 4.If the digit of the unit is removed from the tenth digit then 2 remains .Then find the number?

Answer 1

Tens digit =X
Unit Digit =Y

X+Y=4 .....1

X-Y=2....2

subtracting eq 2 from eq1

2X=6
X=3

&
Y=1

So the number is 10×X+Y =31

$31$