Ritie
8

# The fountain contains 20 pennies and 9 dimes. A coin is randomly taken and not replaced. A second coin is randomly taken. What is the probability that both coins are pennies?

Well, the first coin has chance $\frac{20}{29}$ to be a penny. When it is a penny, the only valid case (the other case gives 0 for the multiplications later, so it is ignored) gives $\frac{19}{28}$ chance for the second one to be a penny. The result is $\frac{20*19}{29*28}$, which is $\frac{95}{203}$, or about 46.80% (rounded to the first 2 decimals)