lestion B3 An online shop has 22 types of canned food and 18 types of frozen food to be launched next week. The online shop plans to select some types of food for discount. (1) Find the number of ways to select 2 types of canned food and 2 types of frozen food to put on discount. The discounts of the 4 types of food are the same. (2 marks) (ii) Find the number of ways to select 3 types of canned food and 1 type of frozen food to put on discount, such that 2 of the selected types will be on 75% discount and 2 of the selected types will be on 50% discount. (4 marks) b) There are 100 coins in a box including $7 $5 coins and all the remaining ones are $10 coins. Suppose two coins will be randomly selected from the box WITH replacement. Let X be the total amount of the two selected coins. i) Construct the discrete probability distribution of X. Correct the probabilities to 4 decimal places. (4 marks) ii) Find the mean of X. (2 marks) (iii) Find the variance of X