Question

If you subtract 0.3 from a certain number then add 0.4 of the original number, then another 2.78, you'll get 25. what was the original number?

Answer 1

x equals 16.0857

Answer 2

Assume that the number we are looking for is x.
We are given that:
1- subtract 0.3 from the number
The expression becomes: x - 0.3
2- add 0.4 of the original number
The expression becomes: x-0.3+0.4x
3- add another 2.78
The expression now becomes: x-0.3+0.4x+2.78
4- the result is 25
Theredore, the final expression is:
x-0.3+0.4x+2.78 = 25

Solve this expression for x as follows:
x-0.3+0.4x+2.78 = 25
1.4x + 2.48 = 25
1.4x = 25-2.48
1.4x = 22.52
x = 22.52/1.4
x = 16.0857