There are 12 yellow marbles in a bag of 18 marbles. How many more yellow marbles would need to be added to change the ratio of yellow marbles to total marbles to 3:4?

add 6 yellow marbles

Step-by-step 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