Using standard mathematical symbols, e.g. +, -, x, etc., rearrange (4) fives to equal the numbers one to ten. For example, 5/5 + 5 – 5 = 1, 5/5 + 5/5 = 2, etc.
Note : you can use decimal point (.) only once.
Below are 10 skittles in an upside-down triangle shape, can you move the skittles around such that the triangle is the correct way up? You can move any skittle left or right, but, at most, you are only allowed to move three skittles up or down!
What does this equation simplify to?
(x – a) * (x – b) * (x – c) * … * (x – z) = ?
In the above figure, the rectangle at the corner measures 6 cm x 12 cm. What is the area of the circle?
A large fresh water reservoir has two types of drainage system. Small pipes and large pipes. 6 large pipes, on their own, can drain the reservoir in 12 hours. 3 large pipes and 9 small pipes, at the same time, can drain the reservoir in 8 hours. How long will 5 small pipes, on their own, take to drain the reservoir?
100 prisoners are locked up in individual cells, unable to see, speak or communicate in any way with each other. There is a central living room with a single light bulb, the bulb is initially off and no prisoner can see the light bulb from their own cell.
Every day, the warden picks a prisoner at random, and that prisoner goes to the central living room. While there, the prisoner can toggle the bulb if they wish (off to on, or on to off). At any point, any prisoner can claim that all 100 prisoners have been to the living room. If they are wrong then all 100 prisoners will locked up forever! However, if they are correct all of the prisoners are set free.
Before the random picking begins, the prisoners are allowed to discuss a plan. What is their best plan to determine when all 100 prisoners have visited the living room?
Can you find a seven digit number which describes itself. The first digit is the number of zeros in the number. The second digit is the number of ones in the number, etc. For example, in the number 21200, there are 2 zeros, 1 one, 2 twos, 0 threes and 0 fours.
