Answer:
The number is 30.
Step-by-step explanation:
The number = x
25 - 1/2(x) = 10
Mutliply both sides by 2, because you does not want the fraction
50 - x = 20
Now, you have no more fraction. Just move 50 to the right side and change its sign
-x = 20-50
-x = -30
Change its sign
x = 30
So, the number is 30.
Hope it helps!