SKH121 wrote:

The 200 seventh graders at John Witherspoon Middle School raised 80% of the funds needed for a field trip. The school donated the remaining 20%. When they went to purchase the tickets, however, they were given a 10% bulk rate discount after a $20 processing fee. Faced with an unexpected surplus the students chose to buy each member of the class one cookie and were still left with $18, which they gave to the bus driver. If each of the cookies cost $0.30, how much did the trip cost the school?

A)$40

b)$80

C)$120

D)$160

E)$200

In the answer explanation, it stated that" added the processing fee back again after subtraction", I couldn't get this point?

If anyone can help in the solution Please.

Hi,

I wouldn't say that the language is too great.

But the explanation..

I assume that the money collected was knowing there is a processing fee of $20..

so there is a discount of the remaining amount as that is the one that constitutes the rate part, that is rate per person *200..

discount or saving = 0.1(x-20)..

now money used is 0.3 * 200 for cookies and 18 for the driver so 0.3*200+18=60+18=78...

Thus equating savings with the expenditure thereafter =>

0.1(x-20)=78..

0.1x-2=78...

0.1x=80 or x=800

But the school spends 20% of it so 800*20/100=160

_________________

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