How Many Rate Questions on the GRE? (Max. 3)

How Many Rate Questions on the GRE? (Probably 3)

For all the fear that they inspire, rate questions are a relatively rare breed on the GRE. At most, you will probably see three such questions out of the 40 total questions.

Rate questions can be broken down into work rate questions and distance problems. Each test will probably have one of each, and maybe two of the one questions. That is, it is very unlikely that you will see three work rate problems.

Below is an example of each of these question types.

1. Mike, Steve, and Daryl take turns driving on a road trip. Mike drives at an average of 60 mph, Steve drives at an average of 5o mph, and Daryl, the daredevil, drives at 80 mph. If Mike drives for 4 hours, Steve drives for 3 hours, and Daryl drives for 90 minutes, approximately what percent of the total miles does Daryl drive?

1. 15%
2. 18%
3. 20%
4. 24%
5. 32%

2. Jason can stack two shelves in 3 hours and Maria can stack three shelves in 2 hours. How long will it take them together, working at a constant rate, to stack thirteen shelves?

1. 5 hours
2. 6 hours
3. 6.5 hours
4. 11 hours
5. 12 hours

These questions are of medium difficulty. You’d likely seem them in the middle section, though they could show up in either the easier or the harder section. At least to the best of my knowledge, there is not a greater likelihood that any question type is more common at lower or higher levels.

Answers and explanations

1. First we have to find the total distance the three traveled: 60×4 = 240; 50×3 = 150; 80×3/2 = 120. 240 + 120 + 150 = 510. Daryl drove a total of 120 miles. Therefore, he drove 120/510 or the total distance. For a quick way to convert to percent, make 120/510 and make it 120/500 = 12/50 or 24%. Answer: (D).

2. A good way to attack this problem is to determine how many shelves per hour each one stacks. Jason stacks 2/3 shelves per hour; Maria stacks 3/2 shelves per hour. Together they stack 2/3 + 3/2 =  13/6 shelves per hour. To stack thirteen shelves they would need 6 hours. Answer: (B).

Final Note

Like many of the tough word problem question types probability, combinations/permutations —rate questions intimidate many. Remember, that the question isn’t that common. Also remember that you don’t have to practice with the hardest rate questions, unless you are getting the easier questions correct. As long as you solved the questions above you are doing well on rate problems and, most likely, they shouldn’t pose too much of a difficulty test day.