We can rent a canoe for x cents per minute for the first 30 minutes and then y cents for each additional minute. How much will it cost to rent a canoe for z minutes, where z>30?  Options:
A) 30y+(z-30)x	B) 30x + zy	C) 30x+(z-30)y	D) 30x + 30y	E) x + (z-30)y
The first 30 minutes cost 30x.   The next (z-30) minutes cost (z-30)y.   The total cost is 30x+(z-30)y.   The answer is 30x+(z-30)y.
<result>C</result>
We can rent a canoe for x cents per minute for the first 30 minutes and then y cents for each additional minute. How much will it cost to rent a canoe for z minutes, where z>30?