Some viral math puzzles come from unexpected sources, like elementary school classrooms. This problem was intended for more advanced students, and it's been stumping people for at least 145 years.
The question below, recently featured by the YouTube channel MindYourDecisions, allegedly appeared on MIT's 1876 entrance exam in the days before the SATs. Though it was written with brilliant young thinkers in mind, you don't need to be a math whiz to understand the problem.
A father said to his son, “Two years ago I was three times as old as you, but in fourteen years I shall be only twice as old as you. What were the ages of each?”
Solving it, however, is a different story. One way to tackle it is to use trial and error until you figure out the ages that fit the criteria, but if you're trying to get into MIT, you should probably show your work.
A simple algebra equation is the solution here. The first part is f-2 = 3 (s-2), with f being the father's current age and s standing in for the son's. The father will be just twice as old as his son in 14 years, which makes the second part of the formula f+14 = 2(s+14). The final equation looks like this:
f+14 = 2s+28
- (f-2 = 3s-6)
After working through the problem, you should come up with 50 for the father's age and 18 for the son's. Two years ago, their ages were 48 and 16, and in 14 years their ages will be 64 and 32. You can watch MindYourDecisions do the math in the video below.
If that problem was too tricky for you, see if you can solve this one from a first-grade math assignment.
[h/t Men's Health]
This story originally ran in 2021; it has been updated for 2022.