You reach into a bag of coins and withdraw two coins. What is the probability you withdrew a nickel and then a dime if the bag held five pennies, ten nickels and four dimes ?

Question

sleepyhead314 · Answer

mmm
I'm not the best at probability, but
I know that we should definitely first find out how many coins there are in total

so 
5 pennies + 10 nickles + 4 dimes = [how many coins?]

anonymous · Answer

19 coins

sleepyhead314 · Answer

good :)

then the chance of getting a nickel on the first try is
[number of nickles] / [total number of coins] = ?

anonymous · Answer

Even though they separate the coins into categories, they are still in one group, so combine everything except the nickels and dimes.

anonymous · Answer

20 / 171

sleepyhead314 · Answer

whoa there

number of nickles = 10
total number of coins = 19

10 / 19
is the chance of pulling a nickel on the first try

sleepyhead314 · Answer

then after we take the nickel out
we are left with a total of $18$ coins total
right?

anonymous · Answer

yes

sleepyhead314 · Answer

then the chance of pulling a dime next
is
[number of dimes] / [new total number of coins] = ?

anonymous · Answer

1.8

sleepyhead314 · Answer

oh oh oh oh right
I was taking one step at a time

but the 20 / 171 answer you gave before is correct ^_^"

anonymous · Answer

okay thank you