Astuntman is running on the roof of a train. his combined speed is the sum of the speed of the train and his running speed. the combined speed is 73 miles per hour, and his running speed is 15 miles per hour. find the speed of the train.

Abag contains 3 red marbles, 2 blue marbles, and 2 green marbles. one marble is picked, then another marble. assume that the selections are made with replacement. a) find the probability of picking two red marbles with replacement. b) find the probability of picking a red marble and a blue marble. assume the selections are made without replacement. c) find the probability of picking two red marbles without replacement. d) find the probability of picking a red marble and a blue marble without replacement.