Respuesta :
If James takes a bus in the morning then the probability P(bus-morning)= 1/3
If he takes the bus in the evening then it will be P(bus-evening)= 1/3
P(bus and bus) = P(bus-morning) x P(bus-evening) = (1/3) x (1/3) = 1/9
This is same for other mode of transportation. So...
P(cab and cab) = 1/9 and P(train and train) = 1/3
P(same mode) = P(bus and bus) + P(cab and cab) + P(train and train) = 1/9+1/9+1/9= 1/3
If he takes the bus in the evening then it will be P(bus-evening)= 1/3
P(bus and bus) = P(bus-morning) x P(bus-evening) = (1/3) x (1/3) = 1/9
This is same for other mode of transportation. So...
P(cab and cab) = 1/9 and P(train and train) = 1/3
P(same mode) = P(bus and bus) + P(cab and cab) + P(train and train) = 1/9+1/9+1/9= 1/3