Compound Probability Tree Method

The tree diagram shows the outcomes of rolling a die and flipping a coin.  
What is the probability of rolling an even number and flipping a head?

• ³/₁₂
• ¹/₂
• ⁴/₁₂
• ⁰/₁₂

The tree diagram shows the outcomes of rolling a die and flipping a coin.

What is the probability of rolling a number that is less than 6 and then flipping a head?

• ²/₁₂

• ³/₁₂

• ⁴/₁₂

• ⁵/₁₂

Two dice are rolled and it is recorded whether the result on each is odd or even. What is the probability that one is even and one is odd? Think: what do you do with the numbers on the tree branches?

• 1/2

• 1/4

• 3/4

• 1/3

A box contains 3 brand A batteries and 7 brand B batteries. 30% of brand A batteries are faulty and 40% of brand B batteries are faulty. A battery is selected at random and then checked to see if it is faulty. What is the probability that a faulty brand B battery is selected?

• 0.28

• 1/4

• 0.42

• 0.21

A box contains 3 brand A batteries and 7 brand B batteries. 30% of brand A batteries are faulty and 40% of brand B batteries are faulty. A battery is selected at random and then checked to see if it is faulty. What is the probability that a NON faulty brand A battery is selected?

• 0.21

• 0.09

• 0.28

• 0.25

James started to draw a diagram for rolling two dice and recording whether a 6 is rolled or not. Finish his diagram. What is the probability of rolling 2 sixes?

• 1/36

• 1/6

• 1/12

• 1/2

James starts to draw a diagram for rolling two dice and recording whether a 6 is rolled or not. Finish the diagram and use it to find the probability of rolling no sixes.

• 25/36

• 10/12

• 2/12

• 2/36

A bag contains 3 lemons and 2 limes. A piece of fruit is taken from the bag and not put back. Then a second piece is taken. What is the probability of taking two limes?

• 1/10

• 2/5

• 5/20

• 4/20

A bag contains 3 lemons and 2 limes. A piece of fruit is taken from the bag and not put back. Then a second piece is taken. What is the probability of taking exactly 1 lemon?

• 12/20

• 6/20

• 2/20

• 18/20

In a box are 3 red pens, 4 black pens and 2 green pens. You pick a pen at random and then put it back. Your friend then picks a pen. What is the probability you both pick red?

• 1/9

• 2/9

• 6/9

• 4/9