Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

How many triangles are there in the picture below?

Can you find the ages of a son, father and grandfather based on the following facts?
The sum of the ages of grandfather, father and son is 140 years.
The age of the son in months is the same as the grandfather in years.
The age of the son in days is the same as the father in weeks.

What is the fastest way to double your money?

The dirtier I get, the whiter I look. Who am I?

Can you find the mistake in the below statement?