A spinner has sectors in four colours, red, blue, green and yellow.

P(green) = 0.19       P(yellow) = 0.29

Red and blue are equally likely.

Work out the probability of landing on red?

A spinner has sectors in four colours, red, blue, green and yellow.

P(green) = 0.19       P(yellow) = 0.29

Red and blue are equally likely.

Work out the probability of landing on neither green nor blue?

A spinner has sectors in four colours, red, blue, green and yellow.

P(green) = 0.19       P(yellow) = 0.29

Red and blue are equally likely.

Work out the probability of landing on yellow or blue?

There are 18 numbered balls in a bag. Four balls have the number 3, five balls have the number 6, two balls have the number 7 and the rest of the balls have the number 9.

A ball is taken at random. Find the probability that the ball has the number 6.

There are 18 numbered balls in a bag. Four balls have the number 3, five balls have the number 6, two balls have the number 7 and the rest of the balls have the number 9.

A ball is taken at random. Find the probability that the ball has the number 3 or 9.

There are 18 numbered balls in a bag. Four balls have the number 3, five balls have the number 6, two balls have the number 7 and the rest of the balls have the number 9.

A ball is taken at random. Find the probability that the ball does not have the number 9.

Minh is late for school. Linh is late for school.

In which scenario are these events independent?

• They go to school together.

• They live in different cities and go to different schools.

• They take the same bus to school.

Minh is late for school. Linh is late for school.

In which scenario are these events NOT independent?

• They go to school on the same bus together.

• They live in different cities and go to different schools.

• Minh woke up late and Linh went to see a doctor before school.

There are four balls in a bag. The balls are lettered A, B, C and D. A ball is taken out of the bag at random. Here are three events:

X: a letter before C       
Y: A or C
        Z: a letter after B

Show that X and Y are independent events.

• X happens, P(Y) = 1/2
  X does NOT happen, P(Y) = 1/4

• X happens, P(Y) = 1/2
  X does NOT happen, P(Y) = 1/2

• X happens, P(Z) = 1/4
  X does NOT happen, P(Z) = 1/2

There are four balls in a bag. The balls are lettered A, B, C and D. A ball is taken out of the bag at random. Here are three events:

X: a letter before C       
Y: A or C 
      Z: a letter after B

Show that X and Z are NOT independent events.

• X happens, P(Y) = 1
  X does NOT happen, P(Y) = 1

• X happens, P(Z) = 0
  X does NOT happen, P(Z) = 1

• X happens, P(Z) = 1
  X does NOT happen, P(Z) = 0