In the jar, there are 7 blue marbles, 11 red marbles, and some yellow marbles. If the chance of randomly picking a yellow marble is 1/4, how many yellow marbles are there?
Let y be the number of yellow marbles
There are 11+7+y=18+y total marbles.
y/(18+y)=1/4.
4y=18+y
3y=18
y=6
There are 6 yellow marbles.
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