100 ml of fruit squash
sum the parts of the ratio, that is 2 + 7 = 9 parts
divide 450 ml by 9 to find 1 part
1 part = [tex]\frac{450}{9}[/tex] = 50 ml
squash is 2 parts = 2 × 50 = 100 ml
lemonade is 7 parts = 7 × 50 = 350 ml
total = 100 + 350 = 450 ml
