Question

Tim has two spinners, spinner A and spinner B. Each spinner can only land on red or blue. The probability that spinner A will land on red is 0.5. The probability that spinner B will land on red is 0.6. Tim spins spinner A once and he spins spinner B once. He does this a number of times. The number of times both spinners land on red is 84. Workout an estimate for the no of time both spinners land on blue. I have and attached tree diagram

Answer 1

56 times

Explanation:

To find the probability of both spinners landing on red, we need to multiply the probability of the spinner A landing on red (0.5) by the probability of the spinner B landing on red (0.6):

P(redA and redB) = 0.5 * 0.6 = 0.3

Then, to find the probability of both landing on blue, we do the same:

P(blueA and blueB) = 0.5 * 0.4 = 0.2

Now, if the number of times that both spinners land on red is 84, to estimate the number of times that both land blue, we just need to multiply this number of times by the ratio of P(blueA and blueB) over P(redA and redB):

84 * 0.2 / 0.3 = 56 times