<u>ANSWER: </u>
The ratio of red to blue marbles in bag is 4 : 5.
<u>SOLUTION:
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Given that, there are nine marbles in a bag. And 4 are red marbles and 5 are blue marbles.
We need to find what is the ratio of red marbles to the blue marbles
According to the given information,
Number of red marbles in the bag = 4
Number of blue marbles in the bag = 5
Now, we can find the ratio of red marbles in the bag
Ratio of red marbles in the bag to blue marbles in the bag is given by
Number of red marbles in bag : number of blue marbles in bag = 4 : 5
Hence, the ratio of red to blue marbles in bag is 4 : 5