In an after school program, students must choose to either play on the playground or read a book silently. On one cloudy day, 70% of the students chose to play on the playground, and the rest chose read a book silently. 60% of the students who went to the playground are boys, and 20% who stayed inside to read a book are boys. If a student is randomly selected on this day, what is the probability that the student is a girl?

Question

Brian

Mathematics

5 November, 01:31

In an after school program, students must choose to either play on the playground or read a book silently. On one cloudy day, 70% of the students chose to play on the playground, and the rest chose read a book silently. 60% of the students who went to the playground are boys, and 20% who stayed inside to read a book are boys. If a student is randomly selected on this day, what is the probability that the student is a girl?

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Miley Nielsen · Answer 1

52% chance. We can simplify it by change the first set of percentages to amounts out of 100.

70% = 70 and 30% = 30. We then can multiply those numbers by our "sub"-percentages.

70 * 0.6 = 42 and 30 * 0.2 = 6.

We then convert those two amounts amounts back into percents.

42 = 42% and 6 = 6%

Adding these two we get the percent of boys.

42% + 6% = 48%

Now, to get the percent of girls we take 48% out of 100% to get our end result of 52%.