Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

What goes up but never comes down?

The ages of a father and son add up to 66.
The father's age is the son's age reversed.
How old could they be?
(3 possible solutions).

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

Bobby and Wilbur decided to take their respective car out of the garage and race. None of them cheated and they both stood at the start time and decided to cover a distance in full throttle. The first to reach the mark was to be declared the winner.

Upon reaching the finishing mark, they found out that Bobby's car was 1.2 times faster than Wilbur's. Now, Wilbur had reached the mark about 1 minute and 30 seconds later than Bobby. Bobby's car reached the mark of 60 MPH on average.

Can you calculate the distance between the starting mark and the final mark with the help of the given data?

Can you find out the missing number in the grid?

There’s a girl who has a large family. She has an equal amount of brothers and sisters, but each brother only has half as many brothers and sisters. What’s the correct amount of brothers and sisters?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

Can you make four (4) nines (9) equal 100?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?