Answer:
90 red cars
Step-by-step explanation:
sum the parts of the ratio 3 + 5 = 8 parts
divide 240 by 8 to find one part of the ratio
240 ÷ 8 = 30 ← 1 part of the ratio
3 parts = 3 × 30 = 90 ← number of red cars
5 parts = 5 × 30 = 150 ← number of blue cars