There were x pigeons and y mynahs in a cage. One fine morning p of them escaped to freedom. If he bird keeper, knowing only that p = 7, was able to figure out without looking into the cage that at least one pigeon had escaped, then which of the following does not represent a possible (x, y) pair?
a) (10, 8)
b) (7, 2)
c) (25, 6)
d) (12, 4)
Ans: a) (10, 8)
If the number of maynahs is less than 7, and if 7 birds escaped, at least one pigeon has to escape.