if zoey has a bag of marbles containing 18 red marbles, how many blue marbles should she add to the bag so that the probability of her drawing a blue marble from the bag is 1/4

Respuesta :

Answer:

6

Step-by-step explanation:

18/3 = 6

Add 6 blue marbles to create four sets of 6 marbles . Since only one set of the four are blue marbles , she'd have 1/4 chance of getting one .