Question

If five is subtracted from three times a certain number, the result is 10. What is the number?

Answer 1

let the number be x 
A.T.Q
3x-5=10
3x=10+5
3x=15
x=15/3
x=5

Answer 2

The unknown number = x (assume)
Three times the number = 3x

Five subtracted from three times the unknown number = 3x-5

The result is 10.

So, the equation is 3x-5 = 10
                              3x = 10 + 5
                              3x = 15
                                 x = 15/3
                                  x = 5  ---> Answer

The number is 5