Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

Why is the Hole below a Lock?

He runs but never walks. Murmurs, but never talks. Has a bed, but never sleeps. And has a mouth, but never eats?

In the image below, you can see two glasses and two matchsticks.You need to move four matchsticks in such a manner that the crosses come inside the glasses. Note: you cannot move the crossed.

Can you find a five letter word that is left with only two letters if one is removed?

What numbers should go on the bottom line?
3 6 9 15
8 2 10 12
11 8 19 27
19 10 29 39
? ? ? ?

What's a single-digit number with no value?

I am white when I am dirty, and black when I am clean. What am I?

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day