Use P(A | B) = P(A and B) ÷ P(B)

Question 1

Phone survey: Android: under 18 31, 18+ 21 iPhone: under 18 37, 18+ 5 A person aged 18+ is chosen at random. Find P(iPhone | 18+) as a fraction in simplest form.

Answer (as a fraction)

Question 2

The probability it rains tomorrow is 0.6. If it rains, the probability the bus is late is 0.75. What is the probability that it rains and the bus is late?

Answer 

Question 3

P(B) = 0.2 and P(A and B) = 0.05. Find P(A | B).

Answer 

Question 4

Phone survey: Android: under 18 20, 18+ 17 iPhone: under 18 10, 18+ 19 A person aged 18+ is chosen at random. Find P(iPhone | 18+) as a fraction in simplest form.

Answer (as a fraction)

Question 5

The probability it rains tomorrow is 0.4. If it rains, the probability the bus is late is 0.2. What is the probability that it rains and the bus is late?

Answer 

Question 6

P(B) = 0.25 and P(A and B) = 0.1. Find P(A | B).

Answer 

Question 7

Phone survey: Android: under 18 32, 18+ 33 iPhone: under 18 23, 18+ 14 A person aged 18+ is chosen at random. Find P(iPhone | 18+) as a fraction in simplest form.

Answer (as a fraction)

Question 8

The probability it rains tomorrow is 0.5. If it rains, the probability the bus is late is 0.75. What is the probability that it rains and the bus is late?

Answer 

Question 9

P(B) = 0.5 and P(A and B) = 0.3. Find P(A | B).

Answer 

Question 10

Phone survey: Android: under 18 11, 18+ 8 iPhone: under 18 38, 18+ 7 A person aged 18+ is chosen at random. Find P(iPhone | 18+) as a fraction in simplest form.

Answer (as a fraction)

Question 11

The probability it rains tomorrow is 0.3. If it rains, the probability the bus is late is 0.8. What is the probability that it rains and the bus is late?

Answer 

Question 12

P(B) = 0.2 and P(A and B) = 0.15. Find P(A | B).

Answer 

Question 13

Phone survey: Android: under 18 10, 18+ 25 iPhone: under 18 30, 18+ 21 A person aged 18+ is chosen at random. Find P(iPhone | 18+) as a fraction in simplest form.

Answer (as a fraction)

Question 14

The probability it rains tomorrow is 0.4. If it rains, the probability the bus is late is 0.2. What is the probability that it rains and the bus is late?

Answer 

Question 15

P(B) = 0.5 and P(A and B) = 0.375. Find P(A | B).

Answer 

Question 16

Phone survey: Android: under 18 29, 18+ 18 iPhone: under 18 13, 18+ 6 A person aged 18+ is chosen at random. Find P(iPhone | 18+) as a fraction in simplest form.

Answer (as a fraction)