SOLUTION: My son has given me this problem to solve as a practice to a test. A field trip cost $960 in total. 10 students are not able to attend so it will now cost the remaining student

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Question 31221: My son has given me this problem to solve as a practice to a test.
A field trip cost $960 in total. 10 students are not able to attend so it will now cost the remaining students, who are going, an extra $16 each. How many students are going on the trip? I am able to give him the answer to the question but I can't figure out how to write down the question in an algrebra form nor can I remember how to solve it. Can you please help me? Thank you
Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
Let the normal amount off student be x
If 10 students can't attend the expression will be: x-10

Equation:



960%28%28x%29-%28x-10%29%29=16%28%28x%29%28x-10%29%29

9600=16%28x%5E2-10x%29

16x%5E2-160x-9600=0

x%5E2-10x-600=0

In quadratic formula, a=1, b=-10, c=-600

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ 

x=%28-%28-10%29%2B-sqrt%28%28-10%29%5E2-4%2A1%2A-600%29%29%2F%282%2A1%29

x=%2810%2B-sqrt%28100%2B2400%29%29%2F2

Remove the negative:

x=%2810%2Bsqrt%282500%29%29%2F2

x=(10+50)/2

x=30

Hence, the total number of students attending was 30.

Paul.