Tricky A-levels maths question stumps grown adults – so see if you can solve it

It's A-Level results day and nervous students around the country will finally learn how they did in their exams. While some will pass with flying colours, others will go through clearing and some will just be looking forward to leaving their studies behind altogether.

It feels like a very long time since we sat our A-Levels, so how do you think you would fare in 2025? In celebration of the momentous occasion, see if you can answer this paper 3 maths question. It was posted by TikTok user @freemathstutor_uk and has left many grown adults scratching their heads.

So get out a sheet of paper, grab a pen and see how you get on with solving the problem below...

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Question

"A team game involves solving puzzles to escape from a room. Using data from the past, the mean time to solve the puzzles and escape from one of these rooms is 65 minutes with a standard deviation of 11.3 minutes.

"After recent changes to the puzzles in the room, it's claimed the mean time to solve the puzzles and escape has changed. To test this claim, a random sample of 100 teams is selected.

"The total time to solve the puzzles and escape for the 100 teams is 6,780 minutes. Assuming the times are normally distributed, test at the 2% level the claim the mean time has changed."

How to solve

Yelp, for a lot of us that question will seem pretty intimidating. But thankfully, the tutor revealed how to solve it.

First up, you'll need to define or state what a mean is, which is the total of the numbers divided by how many numbers there are.

Then, you must state how the data is originally distributed. Once he shows the set-up that's been given, you can then calculate the answer.

We're about to reveal the answer below – so stop scrolling now unless you want to see some spoilers!

Answer

The tutor concluded there was evidence to show the mean time is different.

His answer read: "Therefore we reject the H0 (null hypothesis) and there is sufficient evidence to show the mean time has changed."

Thousands of people have liked the video since it was posted to TikTok – and many took to the comments section to share their thoughts.

One TikTok viewer said: "Amazing thank you!" While another person added: "I'm so cooked."

A third asked: "Why is the mean for the sample set still 65? Should it not be 67.8?"

And the tutor clarified: "No it's the mean for the distribution of sample means which is still the same as the original population mean, so it remains 65."

So did you get the maths question correct? Don't forget to let us know in the comments section below.