SOLUTION: A math class planned a field trip to a computer center. The trip cost $240 to be paid equally by each student. 4 students suddenly can't go. This increased the cost by $2 per stude

Question 143386This question is from textbook algebra: structure and method: book1
: A math class planned a field trip to a computer center. The trip cost $240 to be paid equally by each student. 4 students suddenly can't go. This increased the cost by $2 per student. How many students went to the computer center? HELP MUCH APPRECIATED!!!! This question is from textbook algebra: structure and method: book1

Found 2 solutions by jim_thompson5910, stanbon:
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
Let n=# of total students and c=cost per student (assuming they all go)

So if everyone goes, then the total cost $240 is divided equally among all n students. So the individual cost is

However, if 4 don't go, then simply subtract 4 from n to get . Now divide 240 by to get the individual cost plus $2

Plug in

Multiply both sides by the LCD . This will clear the fractions

Distribute

Distribute again

Subtract 240n from both sides.

Combine like terms

Factor the right side (note: if you need help with factoring, check out this solver)

Now set each factor equal to zero:
or

or Now solve for n in each case

So our possible answers are

or

However, since a negative number of students doesn't make any sense, this means that our only answer is

So there are a total of 24 students. Since 4 can't go, there are only 20 students who went to the computer center.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A math class planned a field trip to a computer center. The trip cost $240 to be paid equally by each student. 4 students suddenly can't go. This increased the cost by $2 per student. How many students went to the computer center?
-----------
Let original number in class be "x"
Total cost for the group was 240x dollars
-------------------------
Average cost when 4 cannot go : 240x/(x-4)
--------------------------
EQUATION:
new average - old average = 2 dollars
240x/(x-4) - 240 = 2
240x/(x-4) = 242
240x = 242x - 968
2x = 968
x = 484 (# of students who planned to go to the computer center)
x-4 = 480 (# of students who actually went)
===============
Cheers,
Stan H.
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