21

25

23

36 (1+1) x (1+1) = 4 (2+2) x (2+2) = 16 (3+3) x (3+3) = 36

9

6 ÷ 2 = 3, 1 + 2 = 3
3 (3) = 9

18 years old

Option B) 2 + 2 x 2 = 2 + 4 = 6

57

70 people

3^2=4+5
(Note ^ refers to the power symbol)

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.

10%

70
75
85
+ 80
310 ÷ 3 = 100 remainder 10