This is confusing. Someone help me please

1 a) Yogurt : Orange Juice : milk
50 : 100 : 250
(50 : 100 : 250 ) / 50
ans= 1 : 2 : 5
b) 1 l = 1000 ml of milk
so 1000/250 = 4
ans= 4 regular smoothies.
c) 3 regular and 1 small
(50 : 100 : 250 ) *3 + (50 : 100 : 250 ) / 2
= (150 : 300 : 750 ) + (25: 50: 125)
ans = 175 ml yogurt, 350 ml orange juice, 875 ml milk