Question

On a spinner, there are twenty equal-size sections numbered from 1 - 20. Which spinner game is fair? A. If you spin more than 20, you win. B. If you spin a number greater than 10, you win. C. If you spin a multiple of 3, you win. D. If you spin a number greater than 4, you win.

Answer 1

The only option here that would be fair is LETTER B.
Option A gives you no chance to win.
Option B gives you 50/50 or .5 chance to win.
Option C gives you 6/20 or .33 chance to win.
Option D gives you 16/20 or .8 chance to win.

Option B is fair.

Answer 2

B. If you spin a number greater than 10,

Explanation:

In order for the game to be fair it´d have to have the same probability of a successfull outcome for both the player and the house, this should be a 50-50 percent chance of winning, when you are going to spin a spinner your total number of outcomes will be 20, if you get a number higher than 10 you win, thats

11, 12, 13, 14, 15, 16, 17, 18, 19, 20, thats a total of 10 possible positive outcomes for the player, and the positive outcomes for the house are:

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, that the same 10 possibe positive outcomes for the house,

thats
`(10)/(20)` for the house and
`(10)/(20)` for the player.

Its a 50-50 percent chance of winning for both.