A shop sells only Apples, Bananas and Mangos. The ratio of Apples to Bananas is 5:11. The next shopper will choose one piece of fruit at random. The probability that they buy a Mango is 0.2. What is the probability that they buy an Apple?

We have the probability of choosing a Mango is 0.2 so the probability of choosing an Apple or Banana is 1-0.2=0.8.Next we use the ratio 5:11 to see that for every (5+11)=16 Apples or Bananas, 5 will be Apples and 11 will be Bananas.So 5/16 x 0.8= 0.25 is the probability of choosing an Apple.