Tim has two spinners, spinnerA 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 spinnerB will land on red is 0.6. Tim spins spinner A once and he spins spinnerB 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.

An estimate for the number of times that both spinners land on blue is 69 times.

Step-by-step explanation:

Let's call x the number of times that Tim spins spinner A. x is also equal to the number of times that Tim spins spinner B because the question said that Tim spins spinner A once and he spins spinner B once.

Now, we can formulate the following equation:

0.5*x + 0.6*x = 84

Because 50% of the times that Tim spins spinner A, that spinner will land on red and 60% of the times that Tim spins spinner B, that spinner will land on red.

So, solving the equation for x, we get:

0.5*x + 0.6*x = 84

1.1*x = 84

x = 84/1.1 = 76.3636

Now, an estimate for the number of times that both spinners land on blue can be calculated as:

0.5*x + 0.4*x

Because 50% of the times that Tim spins spinner A, that spinner will land on blue and 40% of the times that Tim spins spinner B, that spinner will land on blue.

Finally, replacing x by 76.3636, we get

0.5 (76.3636) + 0.4 (76.3636) = 68.7272

it means that an estimate for the number of times that both spinners land on blue is 69 times.