Complete question :
Anna has a box of chocolates. In the box there are milk, plain and white chocolates in the ratio 4:3:2. The box contains 72 chocolates altogether. Anna doesn't like white chocolates. Work out the probability that she will pick a chocolate that is not white?
Answer:
7 / 9
Explanation:
Calculate the number of each type of chocolate :
Milk : plain : white = 4 : 3 : 2
Total ratio = (4 +3 +2) = 9
Milk = (4/9) * 72 = 32
Plain = (3/9) * 72 = 24
White = (2/9) * 72 = 16
Probability of picking a chocolate that is not white :
Number of non-white :
(plain + milk) = (24 + 32) = 56
Probability = (required outcome / Total possible outcomes)
P(not white chocolate) = (number of non-white / total number of chocolates)
= 56 / 72
= 7 / 9