"He starts both trains at the same time. Train A returns to its starting point every 12 seconds and Train B returns to its starting point every 9 seconds". Basically, what you need to do is find the least common multiple. The least common multiple of 12 and 9 is 36, so the least amount of time, in seconds, that both trains will arrive at the starting points at the same time is 36 seconds.
D) Gabriella can exchange 100 U.S. dollars for every 75 euros.
Not reasonable, there are 100 pennies in a dollar so the actual equation is 100d
the answers are b c d and e
