At a speed of 50mph, a certain car uses 1 gallon of gasoline every 30 miles. If the car starts with a full 12 gallon tank of gasoline and travels for 5 hours at 50 mph, the amount of gasoline used would be what fraction of a full tank?
I chose 2/3.
The answer is 25/36
Please explain how to get the answer.
fraction question
This topic has expert replies
At a speed of 50mph, a certain car uses 1 gallon of gasoline every 30 miles.
distance travelled: 5*50 = 250 milestravels for 5 hours at 50 mph
gas used: 250/30 = 25/3 gallon = x
the amount of gasoline used would be what fraction of a full tank?
x is what fraction of 12?
x/12 = (25/3)/12 = 25/36
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Because you did 8/12 instead of 8.33/12.tj123 wrote:i did 250/30 = 8.33
then i did 8/12 which = 2/3
why is this way wrong?
i used the same method as you used?
Let's convert 8.33 to a fraction to make the math easier.
8.33 = 8 and 1/3 = 25/3
(25/3)/12 = (25/3)*(1/12) = 25/36.
25/36 is only 1/36 more than 2/3. When the answers are that close together, it's not safe to round off.
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GMAT is multiple choice.niraj_a wrote:stuart,
this was certaonly helpful, but would a nitty-gritty on these lines show up on the real GMAT?
If they do not say to approximate then do not.
They will provide a fractional answer like 25/36 and you can chose that.
They will not check your work.