Well, we know enough information to make some equations and solve them. Things we know: 1) 52 legs total 2) Ducks have 2 legs 3) Cows have 4 legs 4) No other legs are being counted 5) 4 more cows than ducks We have 2 unknowns: # of ducks, we'll call that D, and # of cows,...

I'd need to see the exact question to be sure, but I think the explanation below should help. Mode should be the same.  Whichever # is repeated most often.  If you have multiple repetitions of an unknown, it could end up being your mode. Example A: 2, 4, 5, 3, 4, 6, x, 4, 2 =>...