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Printjmc
prealgebra senior
Problem
On my ping-pong team there are four times as many right-handed boys as left-handed boys. Of the students on the team who are left-handed, there are twice as many girls as there are boys. Half of the girls who are on the team are left-handed. If there are 36 people on the team, how many are right-handed boys? (Assume no player plays ping-pong equally well with both hands.)
Solution
Let the number of left-handed boys be . Since there are four times as many right-handed boys, the number of right-handed boys is . Since there are twice as many left-handed girls as left-handed boys, and there are left-handed boys, there are left-handed girls. We place all of this in a Venn diagram:
We also know that half the girls on the team are left-handed. Since there are left-handed girls, there are also right-handed girls.
There are a total of people on the team, so . We are trying to find the number of right-handed boys. This number is
We also know that half the girls on the team are left-handed. Since there are left-handed girls, there are also right-handed girls.
There are a total of people on the team, so . We are trying to find the number of right-handed boys. This number is
Final answer
16