Grogg has two bags of marbles, each of which contains some red marbles and some blue marbles (and no marbles of any other color). The ratio of red marbles to blue marbles in the first bag is $3:5.$ The ratio of red marbles to blue marbles in the second bag is $3:2.$ When the two bags of marbles are mixed together, the ratio of red marbles to blue marbles is $11:9.$ What is the ratio of the number of marbles in the first bag to the number of marbles in the second bag?

2:7

Step-by-step explanation:

Let x and y be two positive whole numbers. They may or may not be equal.

The first bag has the ratio of red to blue as 3:5, which scales up to 3x:5x after multiplying both parts by x. We have 3x red and 5x blue.

The second bag has the ratio 3:2 which scales up to 3y:2y. This bag has 3y red and 2y blue.

We can make a handy table to keep track of all the expressions

          red        blue

bag 1   3x        5x

bag 2   3y       2y

Based on that, we can then say:

The two red quantities add to R = 3x+3y

The two blue quantities add to B = 5x+2y

Effectively, I added down along each column of that table.

Divide the two expressions for R and B to lead to the fraction 11/9, which is directly from the ratio 11:9

So,

(total red)/(total blue) = 11/9

R/B = 11/9

(3x+3y)/(5x+2y) = 11/9

Let's cross multiply and then solve for y

(3x+3y)/(5x+2y) = 11/9

9(3x+3y) = 11(5x+2y)

27x+27y = 55x+22y

27y-22y = 55x-27x

5y = 28x

y = 28x/5

y = (28/5)x

y = 5.6x

We'll keep this in mind for later.

Now let:

F = amount of marbles in the first bag

S = amount of marbles in the second bag

Recall that we had 3x red and 5x blue for the first bag. That means we have 3x+5x = 8x marbles in the first bag. Therefore, F = 8x.

Also, we had 3y red and 2y blue for the second bag.

So we have S = 3y+2y = 5y

Then we can apply further substitution to say

S = 5y

S = 5(5.6x) plug in y = 5.6x

S = 28x

In short,

F = 8x

S = 28x

for some positive whole number x. We don't have enough info to pin down what x is exactly; however, it doesn't really matter. This is because the x variable will cancel when dividing F over S

F/S = (8x)/(28x) = 8/28 = 2/7

The fraction 2/7 leads directly to the final answer of the ratio 2:7

In other words, the ratio 8x:28x simplifies fully to 2:7 after dividing both parts by 4x.

what is the graph

step-by-step explanation: