Can you replace the question mark with the correct number?

What is both possible and impossible at the same time?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

You need to climb ten stairs. At every stair, you can either take one step up or you can jump two steps up.

In how many different ways you can climb 10 stairs?

You have three orange, two pink and five purple balls in the drawer beside your bed. There is no electricity and the room is entirely dark. How many balls must you take out to ensure at least one ball of each colour at least?

The picture shows the dice results in each couple of throws. If they are actually following a pattern, can you find out the missing one?

Can you fill the blank with the correct number?

6 30 870 756030 _____

You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?

There are three houses in a straight row. One is red, one is blue, and one is white. The red house is left of the middle. The blue house is right of the middle. Where's the white house?

Which English verb becomes past tense just by rearranging the letters?