Answer:
56
Explanation:
Let N be the total number of spins.
Probability of A on Red and B on Red = 0.5 x 0 .6 = 0.3 (top branch of tree)
Therefore with N spins, the estimated number of times spinner A and spinner B land on red is 0.3N and we are given this as 84
So 0.3N = 84
N = 84/0/3 = 280
The probability of spinner A on blue and spinner B on blue is 0.5 x 0.4 = 0.2 (lowest branch of tree)
For 280 spins, the estimated number of times that both spinners land on blue is given by 0.2 x 280 = 56