Answer:
20
Step-by-step explanation:
We know that the difference between a hundred and a number is four times that number.
So assuming the number to be x, we can write the difference between a hundred and a number as 100 - x and four times that number as 4x.
So by combining these together, we get:
100 - x = 4x
100 = 5x
x = 100/5
x = 20
Therefore, the unknown number is 20.
