Need help with Time, Rate, & Distance word problem

M

max

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Jun 1, 2007
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At the Indianapolis 500, Carter and Daniels were participants. Daniels' motor blew after 240 miles and Carter was out after 270 miles. If Carter's average rate was 20 mph more than Daniels' and their total time was 3 hours. How fast was each averaging?
How can I solve this?

thanks
 
max said:
At the Indianapolis 500, Carter and Daniels were participants. Daniels' motor blew after 240 miles and Carter was out after 270 miles. If Carter's average rate was 20 mph more than Daniels' and their total time was 3 hours. How fast was each averaging?
How can I solve this?

thanks
Click to expand...
As usual start naming names:

What did the problem ask you to solve?

How fast was each averaging?

So we start

Average speed of Daniels = D..........................................(1)

Next information we have:

Carter's average rate was 20 mph more than Daniels'

Average speed of Carter = C = D + 20..................................(2)

Now continue....

Please show us your work, indicating exactly where you are stuck, so that we know where to begin to help you.

Paul - I read your note too late. I decided to leave my work - just in case it helps somebody else (and I spent all this time typing it.......... :evil: )
 
Thanks a bunch for the link
I was stuck here: 3x^2 - 450x - 4800 = 0
I was using the quadratic formula and couldn't get a perfect square root.
I didn't think to divide the equation by 3.
 
Subhotosh Khan said:
Paul - I read your note too late. I decided to leave my work - just in case it helps somebody else (and I spent all this time typing it.......... :evil: )
Click to expand...

No, I'm glad you did. The other solution is much more spoon-feeding than thoughtful anyway. On first-time posts, folks, we have to do more than restate the question. We have to see something of what your thoughts are and where you're having trouble. Unlike the link I provided, we don't just do all the work here.

Max, Glad you saw the division by 3... makes things a lot easier. This is obviously a reused problem (over and over again), but that debate is another story....

-Paul
 
Divide the givens by 3: 240/3 = 80, 270/3 = 90, 3/3 = 1

80/x + 90/(x + 20) = 1
 
max said:
... I was stuck here: 3x^2 - 450x - 4800 = 0

I was using the quadratic formula and couldn't get a perfect square root.

I didn't think to divide the equation by 3.
Click to expand...


Hello Max:

I reviewed some of your posts at this site. Sometimes, you show your work, and other times you simply post the exercise and say nothing about what you've tried or why you're stuck until AFTER somebody responds.

In the future, will you please BEGIN your requests for help by stating what you've tried and why you're stuck?

This will not only increase the odds that you get the help that you need sooner but it will also keep you from potentially wasting somebody's time here.

For example, in this thread, you could have simply stated your second post (quoted above) to being with. In other words, if you only needed help solving the quadratic equation that you had already set up, we don't even need to know the word problem in order to help you. (It also means that Subhotosh spent his time explaining how you could begin to set up an equation that you had already written. That's not really a good use of his time.)

Does my request to you make sense?

Thank you for your future considerations in this regard.

Gobble, gobble,

~ Mark :)

 
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