2018 AMC 10B Problems/Problem 6
A box contains chips, numbered
,
,
,
, and
. Chips are drawn randomly one at a time without replacement until the sum of the values drawn exceeds
. What is the probability that
draws are required?
Solution 1
Notice that the only two ways such that more than draws are required are
,
,
, and
. Notice that each of those cases has a
chance, so the answer is
, or
.