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At a speed of 50 miles per hour

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At a speed of 50 miles per hour

by melguy » Fri Jul 05, 2013 12:33 am
Please clarify my doubt with this problem. Thanks

What is did is
250 / 30 = 8.33

Then divided 8.33 / 12 (ignoring the .33). The closest answer is 2/3 but the OA is 25/36.
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by luckypiscian » Fri Jul 05, 2013 3:14 am
25/36 is a little more than 2/3
the approximation costed you

instead
250/30 * 1/12 = 25/36 :)
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by melguy » Fri Jul 05, 2013 4:23 am
Thanks. Can't believe it that the answer could be so sneaky! lol
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by Uva@90 » Sat Jul 06, 2013 6:25 am
Hi Melguy,
This is how u solved right?

If a car travels for 5 hours at 50 miles per hour, it could travel a distance of

d = 5*50 =250

if 30 miles consume 1 gallon then for 250 miles it take

250/30 = 25/3 gallons

25/3 is what fraction of 12 ?

25/3 = 12*X => So, x = 25/36.

Correct me if I am wrong.[/list]
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by melguy » Sat Jul 06, 2013 8:54 am
Hi Uva

Yes. You did it the right way.
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by cazubuine » Sat Jul 06, 2013 4:57 pm
Forgive me, I am still not sure how you arrive at 25/36 :-(
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by Uva@90 » Sat Jul 06, 2013 7:30 pm
cazubuine wrote:Forgive me, I am still not sure how you arrive at 25/36 :-(
Which part you didn't get or the complete question itself ?
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by melguy » Sat Jul 06, 2013 8:08 pm
cazubuine wrote:Forgive me, I am still not sure how you arrive at 25/36 :-(

Car uses 1 gallon of has every 30 miles.
Car travelled for 5 hours at 50mph. So total = 5 x 50 = 250 miles

Amount of gas used = 250 / 30 or 25 / 3

Full tank was 12. So the amount used would be what fraction of the full tank? =

25
-----
3
---------
12
-----
1

Simplifying

25
-------
3 x 12
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by Matt@VeritasPrep » Tue Jul 09, 2013 4:11 pm
Another way to think about this:

If I use 1 gallon every 30 miles, my ratio of gas used to miles traveled is 1/30. So if I travel 250 miles, I start with this equation:

1/30 = x/250, or x = 25/3.

To get the fraction of a full tank, I just simplify

(25/3)/12

= (25/3) * (1/12)

= 25/36
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