Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

What is common among 11, 69, and 88?

A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?

Create a number using only the digits 4,4,3,3,2,2,1 and 1. So i can only be eight digits. You have to make sure the ones are separated by one digit, the twos are separated by two digits the threes are separated with three digits and the fours are separated by four digits

Can you complete the sequence?

192, 021, 222, 324, 252, 627, 2__, 9__?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

If an earthquake is 1 point higher on the Richter Scale than another earthquake which is actually 10 times stronger, how much stronger would an earthquake be if it was just half a point higher on the Richter scale?

Which is the smallest number that you can write using all the vowels exactly once?

Two men play a dice game involving roll of two standard dice. Man X says that a 12 will be rolled first. Man Y says that two consecutive 7s will be rolled first. The men keep rolling until one of them wins.

What is the probability that X will win ?