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I hate asking answers for math problems, but sadly i really need help!!! Please?
I am totally not a math whiz and i know that math problems aren't always fun to work on, on a Friday night.
But i need help!
It's a question that i'm confused with.
Q: David started across a lake at 15 miles wide in his fishing boat at 10 mph. He had to row the rest of the way at only 5 miles per hour after his motor went out. If he was rowing for half the time that the total trip took, how long did the total trip take?
I'm a bit confused and i don't know how to set up the problem. So please, can you show me how you were able to do it?
1 Answer
- Light CloudLv 71 decade agoFavorite Answer
Let's first start with the unknowns.
The unknowns are:
t : time (how long it took David to get across the lake)
In this case, there's only one unknown.
The relevant equation is d = rt. Distance is equal to the rate * time.
In this case, we know that the distance is 15 miles.
David travelled at two different speeds; he travelled at 10mph for half the time, and 5 mph for the other half of the time. Therefore, he travelled a total distance of 10(t/2) miles using the motor, and then travelled another 5(t/2) miles by rowing.
So the equation would be:
15 = 10(t/2) + 5(t/2)
if you solve, you get that t = 2 hours. That is, for the first hour, David travelled at 10 mph (and travelled 10 miles). Then the motor broke, so David rowed for another hour at 5mph, and travelled an additional 5 miles.
