Question

Put a digit in the gap, such that the answer is a whole number:'

9x–42=5... what are all the possible digits

Answer 1

`7\\\\9x-42=57`

Explanation:

There can be any number from
`0,\ 1,\ 2......,\ 8,\ 9`.

But by addition of that number and 42 should be divisible by 9.

`42+50=92\ \ \ \ \ not\ divisible\ by\ 9\\\\42+51=93\ \ \ \ \ not\ divisible\ by\ 9\\\\42+52=94\ \ \ \ \ not\ divisible\ by\ 9\\\\42+53=95\ \ \ \ \ not\ divisible\ by\ 9\\\\42+54=96\ \ \ \ \ not\ divisible\ by\ 9\\\\42+55=97\ \ \ \ \ not\ divisible\ by\ 9\\\\42+56=98\ \ \ \ \ not\ divisible\ by\ 9\\\\42+57=99\ \ \ \ \ \ divisible\ by\ 9\\\\42+58=100\ \ \ \ \ not\ divisible\ by\ 9\\\\42+59=101\ \ \ \ \ not\ divisible\ by\ 9`

Hence only possible value in the gap is 7.

`9x-42=57\\\\9x=99\\\\x=11`