Friday's puzzle is one of those that can drive you mad. When you first approach it, the problem doesn't appear that hard. Then you start to try to solve it, and things become more difficult, until you become convinced that it is not possible. At this point you will start checking that there isn't a trick, and clarifying the rules - just to make sure!
Then when you finally solve the puzzle (or give up and look at the answer - which is below) the solution is not at all obscure.
So, onto the puzzle . . .
Using the numbers 3 3 8 and 8 in any order, and any of the four arithmetic operations + - x and /, plus brackets (), construct a sum that equals 24.
Obviously 3 x 8 = 24, but you have to use both 3s and both 8s. Also, you can't combine digits, so for example, 33 - (8 / 8) is not allowed.
Square roots, factorials etc. are not allowed, and not needed.
You will have spent quite a while trying to devise ways to produce 3 from 3, 3 and 8, so you can multiply it with the remaining 8. But it's not possible.
Actually what you need to make from the 3, 3 and 8 is one third. Then dividing 8 by this gives 24 . That is 8 / (1 / 3) = 24, but how to do this?
Well 3 - 8 / 3 = 9 / 3 - 8 / 3 = (9 - 8) / 3 = 1 / 3
And the final solution is . . .
8 / (3 - 8 / 3) = 24