A ratio is the number of one item compared to the number of another item. It can be written as a fraction or with a colon between the numbers.
The question wants the ratio of red to blue, so the number for red would be first.
They have 64 red and 31 blue
The ratio would be 64/31
64 and 31 do not have any common multipliers so cannot be simplified.
The answer would be 64/31