A barge has traveled 50 mi of a 500 mi trip. The barge's speed is 30 mph. How many hours will it need to complete the trip?

I think its 15 but I'm not sure ...

We first find out the total time it will take for the whole trip at 30mph.

We simply divide total distance by speed so:

500 / 30 = 16.66 hours

Now what time does it take to travel 1 mile only? Let this time be x

1 hr = 30 miles

x hr = 1 mile

Coss multiplying this equation, we get:

30x = 1

x = 1 / 30 = 0.033 hrs

For 50 miles it will take 0.033 * 50 = 1.65 hours

The remainder of the trip it will take:

16.66 - 1. 65 = 15.01 hours