The ratio of jacks to marbles in the bowl was 2 to 5 If the

The ratio of jacks to marbles in the bowl was 2 to 5. If the bowl contained 350 jacks and marbles, how many were marbles?

WIth questions involving ratios, always place an X next to it.
2:5 becomes 2x:5x

so now

2x + 5x = 350
7x=350
x=50
jacks is 2x so there were 100 jacks.
marbles is 5x so there were 250 marbles