The cost to rent a small bus for a trip is x dollars, which is to be shared equally among the people taking the trip. If 10 people take the trip rather than 30, how many more dollars, in terms of x, will it cost per person?  Choose the correct option
A) x/6	B) x/12	C) x/15	D) 3x/40	E) 3x/80
Just plugging in values   X= 300   Cost per person if we consider 10 = 30   Cost per person if we consider 30 = 10   Difference between costs is 20 dollars.   Plugging in the value of x into the answer choices, let's see which one yields a result of 20. And that is x/15.
<result>C</result>
The cost to rent a small bus for a trip is x dollars, which is to be shared equally among the people taking the trip. If 10 people take the trip rather than 30, how many more dollars, in terms of x, will it cost per person?