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math-question
..since you're good at math, would you mind helping me?
it looks like a simple question, but I keep getting i wrong, here's the question;
In a class with 12 boys and 18 girls, the average height for boys was 180 cm, and for the girls it was 165 cm. What is the class' average?
:S The answer is supposed to be 171 cm.
But I don't know how to get there, and WHY, I keep getting the wrong answer.
Please help?
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Wow, lol. I feel stupid, I'm in calc and it still took me about 5 minutes to figure this one out.
If you want the average of the whole class, you don't want the average of the average of the girls and boys, which would be 180+165/2=172.5
What you want to do is take 180 x 12 (to get the heights of all the boys added together) plus 165 x 18 (to get the heights of the girls, then added to the heights of the boys) then divide by the total number of people in the class (30).
You should get 171.
Hope this helps! :)
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