Percent of earnings that go to school = 80%
Percent of earnings that was spent on the fundraiser cost = 20%
Last year earnings were= $4000
80% of 4000 went to school which is =

20% of 4000 =
went to costs.
a:
As given, this year, they want $4,000 to go directly to the school.
So let the earnings this year be represented by = x
As, 80% of the earnings go to school, so 80% of x = 4000



Hence, this year their earnings should be $5000 so that 80% of it which is $4000 will go to school. And 20% which is $1000 will go to costs.
Or we can say last year they earned $4000, so this year they need to earn $1000 more.
b:
The total amount they need to earn this year is $5000.