363.The Third Shiny Penny
★★★classical probabilityCh. 1 — Classical Probability and Combinatorics444+ Problems in Probability
There are 3 shiny and 4 dull pennies in a box. Pennies are drawn one at a time without replacement. Compute the probability that it takes more than 4 draws for the third shiny penny to appear.
Sign in to submit an answer and track it toward your stats.
Sign inHint
Complement: the third shiny appears within the first 4 draws. Where can the shinies sit among the first four positions?
Want timed drills, mental math, and a market-making game too? Try the full practice suite →