Probability

1

There are 20 counters in a box. 9 are yellow, 4 are black and 7 are green.

What is the probability that a counter which is taken from the box without looking will be green?

2

There are 20 counters in a box. 9 are yellow, 4 are black and 7 are green.

What is the probability that a counter taken from the box without looking will be yellow or black?

3

There are 20 counters in a box. 9 are yellow, 4 are black and 7 are green.

What is the probability that a counter taken from the box without looking will be blue?

4

There are 20 counters in a box. 9 are yellow, 4 are black and 7 are green.

What is the probability that a counter taken from the box without looking will not be black or green?

5

Two 6-sided dice are each marked 1, 1, 2, 2, 3, 3.

Jot down all the possible pairs of numbers that you can get when the two dice are thrown.

The pairs of numbers are added together to get a score. As the dice are only marked from 1-3, there's maximum score of 6.

What's the probability of getting a score of 3?

6

What's the most likely score?

7

What's the probability of getting a score of 6?

8

Melanie has been recording how many times a drawing pin landed point-up after being thrown in the air.

She threw the pin 50 times and found it landed point-up 9 times.

What's the probability of it landing point-up in the next throw?

9

Melanie has been recording how many times a drawing pin landed point-up after being thrown in the air.

She threw the pin 50 times and found it landed point-up 9 times.

What is the probability the drawing pin doesn't land point-up after the next throw?

10

The next day Melanie throws the drawing pin in the air 200 times.

Using her figures from the previous day, roughly how many times could she expect the drawing pin to land point-up?