Brain Challenge: Which Number Should Be in Place of the Question Mark? 

Want to determine how much focus your brain is capable of achieving? This math test will be an excellent method to train your mind to do just that. 

Contrary to popular belief, solving math problems is a lot of fun. And that’s what this quiz brings to the table! If you can solve it, you will be able to distract yourself from your everyday schedule. That’s pretty much the push your brain needs to gain some much-needed focus.

Take your time with this puzzle:

As you can see, the first three equations have exact solutions. Can you get the answer to the fourth one without having to scroll down?

 How to Find the Solution

  • The first equation shows a summation in which the three lipsticks give a result equal to 30.
  • The next equation sums up one lipstick and two mirrors giving a result of 20.
  • Equation 3 represents a summation of two pairs of nail polish and one mirror to give a result of 9
  • The final equation is the one with a question mark. It is a representation of one mirror, one nail polish, and a lipstick.

Did you get an answer?

The Solution


To solve the fourth equation, you will need to use the first three so that you can determine what each component stands for.

  • In the first equation, all three lipstick represent the same number. You find this number by dividing the result by 3 to get 10. Therefore, one lipstick represents the number 10.
  • Taking 10 as your base value for the lipstick, you find that both mirrors represent 10 in equation number 2. Every mirror is then determined to be equal to a value of 5.
  • Taking 5 and adding two pairs of nail polishes will give a value of 9. You can tell that every pair of lipstick represents a value of 2.
  • This only leaves you with one lipstick representing a value of 1.
  • The final equation can then be represented by 5 + 1 x 10

The equation simplifies to 5 + 1 x 10, which gives a value of 15.

The answer is, therefore, 15. 

Did you successfully find the solution to this quiz? Invite your friends to try it out as well and see who gets it right! 

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