Two identical jars are filled with equal numbers of marbles. the marbles are colored red or white. the ratio of red to white marbles is 7: 1 in jar 1 and
9: 1 in jar 2. if there are 90 white marbles all together, how many red marbles are in jar 2?

Let the number of white marbles in Jar 1
Let the number of white marbles in Jar 2
Total number of white marbles is

Jar 1 has white marbles and red marbles so marbles total
Jar 2 has white marbles and red marbles so marbles total
Since both jars have equal amounts of marbles,

We have a system of equations:



The number of red marbles in Jar 2 is so we solve for


⇒
⇒
⇒
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Number of red marbles in Jar 2 is

So there are 360 red marbles in Jar 2.