If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?

Can you find the odd number in the following five choices?

1) 482636
2) 259807
3) 865195
4) 104739
5) 391744

When we see 2 but call 10?

How many times can you subtract the number 5 from 25?

We have arranged an array of numbers below. What you have to do is use any kind of mathematical symbol you know excluding any symbol that contains a number like cube root. You can use any amount of symbols but you have to come up with a valid equation for all of them.

0 0 0 = 6
1 1 1 = 6
2 + 2 + 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

The barber of Town shaves all men living in the town. No man living in the town is allowed to shave himself. The barber lives in that town. Who then shaves the barber of the town?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

What English word has three consecutive double letters?