If 1+9+8=1, what is 2+8+9?

Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'

Solve The below Equation:

ALFA + BETA + GAMA = DELTA

If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

Replace the question mark with the correct number.

2 + 2= 4
3 + 3= 18
4 + 4= 48
5 + 5= ?

What are the next two letters in the following series and why?
W A T N T L I T F S _ _

*Hint: Check Puzzle Title

You are given a set of weighing scales and 12 marbles. The scales are of the old balance variety. That is, a small dish hangs from each end of a rod that is balanced in the middle. The device enables you to conclude either that the contents of the dishes weigh the same or that the dish that falls lower has heavier contents than the other. The 12 marbles appear to be identical. 11 of them are identical, and one is of a different weight. Your task is to identify the unusual marble and discard it. You are allowed to use the scales three times if you wish, but no more. Note that the unusual marble may be heavier or lighter than the others. You are asked to both identify it and determine whether it is heavy or light

Find the last number in the series below:

voN luJ yaM raM ---

What number comes next in the series?

5 15 5 18 5 24 14 20 _

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?