answer all questions with explanation

a. Three distinct integers are chosen at random from the rst 25 positive integers. Find the probability that (i) their sum is an even number (ii) their product is an odd number. I). There are 30 eggs in a box including 10 defectives. A boy selects two eggs randomly and he receives Rs.10 for every good egg, and loses Rs.15 for every defective egg. what is his expected gain? (CLO-1) (MS-points)