Number Puzzles

1

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


2

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?


3

16, 23, 19, 19, 22, 15, 25, ?


What number should replace the question mark?


4

0, 1, 3, 6, 7, 9, 12, 13, 15, 18, ?, ?, ?

What numbers should replace the question marks?


5

What number continues the sequence?
25, 50, 27, 46, 31, 38, 39, ?