Math question about ratios

Question

A bag contains 105 red and blue marbles. The ratio of red and blue marbles is 2 to 5. How many red and blue marbles are in the bag?

Answer 1

2/(2+5) = 2/7 of 105 = 2(105)/7 = 2(15) = 30 red marbles and 105-30 = 75 blue marbles

2/5 = 30/75

2.5 times as many blue as red

5 = 2.5(2) and 75 = 2.5(30)