Question

Karin has 13 coins (2 quarters, 6 dimes, 4 nickels, and 1 penny) in a piggy bank. She turns the bank upside down and shakes the bank until a coin falls out puts itand the shakes until another coin falls out.What is the probability that the first coin is a nickel and the second coin is a quarter?

Answer 1

As the events are independent, taking X as the event that the first coin is a nickel and Y the event that the second coin is a quarter. The probability is

`P(X\text{ and Y)}=P(X)\cdot P(Y)`

So in this case we have that

`P(X\text{ and Y)}=P(X)\cdot P(Y)=(4)/(13)\cdot(2)/(12)=(8)/(156)=(2)/(39)`