Hi! So you have 10 total marbles, 2 yellow, 3 red, and 5 blue. That means that you have a 2 in 10 chance of drawing a yellow, 3 in 10 of drawing a red, and 5 in 10 (or 1 in 2, they're equivalent) of drawing red. Again, the probability of drawing a yellow the first time is a 2 in 10 (or a 1 in 5, equivalent). As the questions says, you multiply the probability of the first even (2/10 or 1/5) by the second (2/10 or 1/5 again because you put the marble back). Doing this you would get 1/25. (You can use a calculator like I did, but I can explain the multiplying more detailed if you want)