# Worksheet: Using Combinations to Find Probability

In this worksheet, we will practice finding the number of outcomes and the probability using combinations.

**Q3: **

A team of four is to be randomly selected from a group of ten boys and ten girls. Determine the probability that a team will contain only girls.

- A
- B
- C
- D
- E

**Q5: **

A computer generates four-digit codes using the numbers 0–9 with no repeated digits. How many unique codes can be generated?

**Q7: **

Which of the following represents the number of ways of selecting 2 students out of 24 for a class activity?

- A
- B
- C
- D

**Q8: **

A small combination padlock can be opened by entering three different specified numbers from 1 to 9 in any order. Adel has 10 attempts to guess the combination. Determine the probability of him opening the lock.

- A
- B
- C
- D
- E

**Q9: **

A bowl contains 25 marbles, each with a different colour. If Amir selects four marbles from the bowl, what is the probability that he selects the marbles with the four colours that he wants?

- A
- B
- C
- D
- E0

**Q10: **

Mariam wants to visit cities across the US, and she has placed the names of 32 cities into a hat. If she randomly draws 3 names from the hat, what is the probability that she gets Savannah, Austin, and Seattle?

- A
- B
- C
- D
- E0

**Q11: **

In how many different ways can 10 motorcycles and 9 bicycles be arranged in 2 spaces if the order is not important?

**Q12: **

Which of the following represents the number of ways in which the letters of the word “zebra” can be rearranged?

- A
- B
- C
- D

**Q13: **

Which of the following represents the number of ways in which 8 different digits can be rearranged to form an 8-digit number?

- A
- B
- C
- D

**Q15: **

Which of the following represents the number of ways of selecting 2 students out of 17 for a class activity?

- A
- B
- C
- D