41

2.5 and 3. In the top sequence the numbers progress × 1.5. In the bottom sequence the numbers progress × 2.5.

34826: each number is the sum of the last two digits of the previous number, preceded by the remaining numbers in reverse.

70

15 + 1x1 = 16
16 + 2x2 = 20
20 + 3x3 = 29
29 + 4x4 = 45
45 + 5x5 = 70

6: the sequence progresses –0, –1, –2 repeated.

Seven.

303
because if we put together the numbers: 21-22-23-24-25-26-27-28-29 and the next are 30 and 31

59
The first 56 balls could be of all colours except red. This would leave 8 balls, all of which are red, so any three chosen would be red.

One thousand is the first number that, when spelled out, contains an a. (One hundred and one if you count the "and.")

Drop the "S".

353
(x*2-1)

Number 194