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A box holds 42 pieces of red construction paper and 18 pieces of blue construction paper. A piece of paper is pulled out of the box at random and then placed back in the box.



How many times can you expect that a piece of red paper will be pulled out of the box in 110 tries?





A.


48


B.


55


C.


60


D.


77
_______________________________________

A bin contains yellow and black balls. A ball is selected at random and then placed back in the bin. The results are recorded after 10 trials, 50 trials, and 150 trials. The results are recorded in the table.



Based on the table, how many times can you expect that a yellow ball will be selected in 300 tries?






Outcome_______Number of trials
_______________10_______50_______150
Yellow_________9________32_______135
Black_________1_________18_________15






Answer :

Hippalectryon
First problem :
probability to draw a red paper : 42/(42+18)=7/10

In 110 tries one can thus expect to draw 7/10*110=77 red papers

Second problem :
Since for 150 trials (which will give the least error) we have got 135 yellow balls, we can expect twice as much in 300=150*2 trials, which makes 270 yellow balls.

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