Answer:
54 percent
Explanation:
The final probability is a weighted average of the going to play probabilities determined for each weather scenario:
P(John performs cello; provided that it rains) * P(it rains) + P(it rains) + P(it rains) + P(it rains) + P(it rains) +
If it doesn't rain, P(John plays cello) * P(it doesn't rain) =
0.54 = 0.6 * 0.7 + 0.4 * 0.3
The likelihood is 54 percent.