Answer:
add 6 yellow marbles
Explanation:
12 yellow marbles in a bag of 18 marbles....if ur adding 1 yellow marble, u are also adding 1 marble to the total of marbles...
so adding 1 makes u have 13 yellow to 19 marbles..13/19 does not equal 3/4
add 2....making it 14 yellow to 20 marbles.....14/20 does not equal 3/4
add 3.....15 yellow to 21 marbles....doe not equal 3/4
add 4....16 yellow to 22...nope
add 5....17 yellow to 23...nope
add 6....18 yellow to 24.....18/24 = 3/4 or 3:4 ratio
I know there has to be an easier way to find this...I just dont know it.
But if u add 6 yellow marbles.....which adds 6 marbles to the total marbles....means u have 18 yellow marbles in a bag of 24 marbles...
18/24 = 3/4......it is now a ratio of yellow to total marbles = 3:4