A student selected at random participating in a sport is exactly the percentage you gave: 40%, likewise for a club: 65%. To find the probability of a student being in both a club and a sport you multiply the probabilities (.4*.65) = .26 = 26%. If you know that 26% are in both, you know that (40-26=14) 14% are only in sports, and (65-26=39) 39% are only in club, therefore 26% are in both and (14+39=55) 55% are in either one so it is less likely a student is in both than either one.
The probability of drawing a heart is: # hearts/ #total = 13/52 = 1/4 = 25%. If you draw a heart and don't replace it, the odds of drawing another heart are now 12/51 = .235=23.5%. If you draw 3 times, replacing each time, you have the same probability each time so it is (13/52)*(13/52)*(13/52) = (.25^3) = .016 = 1.6%. You can construct a tree diagram by putting each of the suits as a branch for the first try, then each of the suits off of each branch for the 2nd and 3rd tries.