GMAT Question of the Day – Problem Solving – Remainders
When positive integer x is divided by either 7 or 9 the remainder is 4. Which of the following is a possible value of x?
GMAT Question of the Day Solution:
Many of my GMAT tutoring students absolutely loathe remainder questions. I think that these questions feel very tricky and opaque. Also, I can imagine that many a GMAT hopeful has wasted a significant amount of time trying out different values for a remainder question only to come up short of an answer. Pretty unsatisfying. The reality is that most of these questions are relatively straightforward. For this question find the least common multiple of 7 and 9 (you can also just multiply the two numbers). Then add 4 to that number and you have found a value that when divided by either 7 or 9 will leave a remainder of 4. That’s it. The other way to do this question if to make a chart (this can be very helpful on certain Data Sufficiency Questions).
Additional GMAT Divisibility and Remainder Practice Questions
Here’s a challenging question from the GMAT Official Guide on which you can use this same remainder strategy, either making a list and cross-referencing or calculating LCM and adding the remainder: Club X has more than 10 but fewer than 40 members
And another GMAT Question of the Day Divisibility question which is a little different but allows you to practice a practical approach to number properties.