How to Conquer GMAT Rate Problems

In "How to Conquer GMAT Rate Problems", Erika John from PrepScholar GMAT discusses one of the most valuable GMAT math strategies — taking complex problems step-by-step.

GMAT rate problems often require a series of steps to get to the answer. This series of steps is often not immediately obvious because there are so many elements to the problem, because the math is couched in a word problem, etc. This means that seeing a clear path to the finish line is difficult with many GMAT rate problems.

This is *okay*. Rather than waste time working out a game plan, the best choice is to figure out just the next step you *can* take given the information you have, then repeat the process. In the case of GMAT rate problems, this is doing the next possible conversion. We walk through exactly what this means by solving one of the real GMAT rate problems from the GMATPrep software.

With this strategy, you're ready for the most conversion-heavy rate problems GMAT test writers throw at you. However, this isn't all — taking problems one step at a time when the solution isn't immediately clear is one of the broader GMAT math strategies, as we can apply it to a variety of multi-step problems. Not sure what to do with a bunch of terms exponents? See how you can combine two or three of them, then see if it simplifies further with your new term. Have a complicated geometric figure? See which angle or side you can solve for now, then see if you can solve for more with the new information.

[jauipop]

Got this question in my practice test and I fumbled (like you said that most students would) and when I actually did it outside of a timed situation (i.e. without panicking), I went "duh". lol

[ashwinrebbapragada]

This is an excellent question and explanation. Thank you for your time and service.

[fazalbangash]

please try to give detail and methods to solve maths problems in GRE ..

[benjamincarter]

So just another way to do this by POS, I wrote down 50, 100, 150, 200, 250. Then right beside it I wrote down 30, 60, 90, 120, 150, 180, 210, 240. Basically getting the 30s as close as possible to the 5 hours for 50s then I put the 8/12 for the 30s for the gallons of gas used and multiplied the 8 and 12 by 3 and got 24/36. All in all it only took about 15 seconds to do it by POS.

[rawanalnajjar]

Thanks A bunch, I hope you talk about the best strategies that we should use to solve other types of problems.

[unnatideep]

There's another easy way to this. Since the speed is constant for the gasoline usage and the driving.
At 50 miles --> 1 gallon/30 mins = 2 gallons/hr
At 50 miles -->? gallon --> 5 hours x 2 gallons = 10 gallons
10(used)/12 (total) = 2/6
Look at the options, E is the square of 2/6
Therefore, option E