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anonymous
 one year ago
John’s piggy bank contained 7 dimes and 3 quarters. He pulled out 1 coin without looking. Without replacing the first coin, John then pulled out a second coin.
What is the probability that both coins were dimes? Express your answer in simplest form.
anonymous
 one year ago
John’s piggy bank contained 7 dimes and 3 quarters. He pulled out 1 coin without looking. Without replacing the first coin, John then pulled out a second coin. What is the probability that both coins were dimes? Express your answer in simplest form.

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0My thought is that it's as simple as 2/10. Im not quite sure though.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0We have two steps for this. I'll help you through them onebyone. The first step is figuring out what the probability is for pulling the first dime out. Which is represented as \[\large \frac{no.~of~dimes}{total~no.~of~coins}\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.07/10 then I would presume?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Yep. So our next step (3 in total, not 2 sorry) is to figure out what the probability of getting a dime would be if there is one less dime and one less coin. Which is represented as \[\large \frac{no.~of~coins~1}{total~no.~of~coins~1}\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0So 6/9. With the reduced dime he would have presumably pulled, it takes one away from the amount of dimes, which in return reduces the amount of coins altogether.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Right, good job. Before we move on to the final step, do you know what 6/9 will simplify to?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Great! So our final step is to multiply the two fractions together, to get the probability of both happening. So \[\large \frac{7}{10} \times \frac{2}{3}=~?\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.014/30, which would reduce to 7/15. 7 is a prime number so that must be my answer.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Cool! Thanks a lot. I appreciate your help!

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Right, it would be 7/15. And also, \[\huge \color{aqua}N\color{fuchsia}o \space \color{lime}P \color{orange}r \color{blue}o \color{maroon}b \color{red}l \color{olive}e \color{purple}m \ddot\smile \]
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