At least/at most problems

Questions asking for probability of 'at least k' or 'at most k' successes, typically requiring complementary probability or summing multiple cases.

1 questions

CAIE S1 2013 June Q2

2 The 12 houses on one side of a street are numbered with even numbers starting at 2 and going up to 24 . A free newspaper is delivered on Monday to 3 different houses chosen at random from these 12. Find the probability that at least 2 of these newspapers are delivered to houses with numbers greater than 14.