Alex counted to 2400 by 6's beginning with 6. Matthew counted to 2400 by 4's starting with 4. How many of the numbers counted by Alex were also counted by Matthew?

Isabelle is mixing red and blue paint to make purple paint she adds 3/10 of a fluid ounce of red to 12/25 of a fluid ounce of blue to make 1 1/30 fluid ounces of purple how many fluid ounces of red paint ounces of red paint will she need to make 3 fluid ounces of purple paint