GMAT Statistics Practice Questions
Starter questions
These are sample questions to ease you into the topic. They cover the basic principles and the simplest forms these questions can take.
A class has two sections: Section A and Section B. The average score on a test for Section A is 80, and for Section B is 90. Section A has 20 students, and Section B has 30 students. What is the overall average test score for the entire class?
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More questions
These are examples that are more reflective of the exam. They include a couple of different steps and test the same concepts in slightly less obvious ways.
In a class of 40 students, 60% study Spanish, 45% study French, and 10% study neither. What percent of students study at least one of these languages?
A set of 20 employee satisfaction scores has a mean of 75, a median of 80, and a mode of 85. What is the minimum number of employees whose scores could be 85?
A workshop manager logs the downtime of every machine at the end of each month. The workshop has 4 cutting machines, and it has twice as many finishing machines as cutting machines. Last month, each cutting machine was down for 2 hours and each finishing machine was down for 5 hours.
Each hour of downtime costs the workshop $90 in lost production revenue. In addition, the repair service bills each machine separately: $40 per hour for the first 3 hours of downtime in a month and $70 per hour for each hour of downtime beyond 3 hours. Here the first 3 hours means hours 1 through 3, and hours beyond 3 means the fourth hour and later.
The total downtime cost of a machine is the lost revenue plus the repair charges for that machine. What was the average (arithmetic mean) total downtime cost per machine last month, across all of the workshop's machines?
One afternoon, a guitar teacher has five lessons. Four durations are 30 minutes, 40 minutes, 40 minutes, and 70 minutes. The fifth lesson is the longest, the mode and the median of the five durations are both 40 minutes, and the range is 50 minutes. For each lesson separately, she collects $2 per minute, sets aside 1/4 of the collection for rent, and then saves 1/3 of the remainder. If one dollar is chosen at random from the total amount she saves from the lessons longer than the median, which of the following must be the probability that it came from the longest lesson? Here longer than means strictly greater than, the range is the greatest duration minus the least duration, and all durations are whole numbers of minutes.
A farmer stores corn seed from the last two harvests in a bin. The bin holds 900 seeds in all. Some were harvested one year ago and are called new seeds, and the rest were harvested two years ago and are called old seeds. Each seed is also either treated with a fungicide or untreated. Of the 900 seeds, 600 are treated, 400 are both treated and new, and 100 are neither treated nor new. Germination tests show that a seed's germination rate depends only on its age, not on whether it is treated. At their current ages, new seeds germinate at 90% and old seeds germinate at 70%. For each additional year a seed is stored, its germination rate drops by 10 percentage points. Next spring the farmer will plant all 900 seeds, when every seed will be one year older than it is now. How many of the 900 seeds are expected to germinate?
Hard questions
These are 705+ level questions that you can expect from the GMAT Focus Edition. They test multi-step reasoning, complicated word problems, and the hardest percent concepts the exam covers.
A payroll audit selects employees for review independently across departments. In Department A, 20% of employees are selected, and in Department B, 30% are selected. If one employee is randomly chosen from each department, what is the probability that at least one of them is selected for review?
A manufacturer tests 30 filter cells on each of three water mixtures, A, B, and C. A cell passes a test if it filters a full standard container of that mixture within one minute. Of the cells, 18 pass the test with mixture A, 17 pass the test with mixture B, and 16 pass the test with mixture C.
The positive numbers of cells passing both A and B, both A and C, and both B and C are in the ratio 3:4:5, respectively. Each of these three counts includes any cells that pass all three tests. Cells may fail all three tests.
What is the least possible number of cells that pass exactly one of the three tests?
At a thrift store, seven employees each spent a positive integer number of hours sorting donated goods last week. No two employees spent the same number of hours sorting. The mean of the seven totals was 8 hours, the median was 8 hours, and the difference between the greatest and least totals was 12 hours. What is the greatest possible combined number of sorting hours for the two employees with the greatest totals?
A consulting firm has 200 employees eligible for performance bonuses. 38% of employees qualify for the client satisfaction bonus, and 32% qualify for the productivity bonus. If 15% of employees qualify for both bonuses, what is the probability that a randomly selected employee qualifies for neither bonus?