1200 red drops and 800 blue drops.
First, find the number of pints of purple paint. There are 8 pints in each gallon, so multiply 50 times 8 to find that there are 400 pints.
Now, multiply the 400 pints times the number of drops of each color. 400 times 3 red drops is 1200 drops, and 400 times 2 blue drops is 800 blue drops.