If it snows tomorrow, the probability is 0.9 that John will practice his guitar. If it does not snow tomorrow, there is only a 0.5 chance that John will practice. Suppose the chance of snow tomorrow is 70%.

Question

What is the probability that John will practice his guitar?

P(John will practice) =
(Type an integer or a decimal.)

Answer 1

P(John will practice) = 0.9 * 0.7 + 0.5 * 0.3 = 0.63 + 0.15 = 0.78

Therefore, the probability that John will practice his guitar is 0.78.