A physical education class has three times as many girls as boys. During a class basketball
game, the girls average 18 points each, and the class as a whole averages 17 points per person.
How many points does each boy score on average?

Question

A physical education class has three times as many girls as boys. During a class basketball 
game, the girls average 18 points each, and the class as a whole averages 17 points per person. 
How many points does each boy score on average?

anonymous · Answer

a trick is to use actual numbers. say there is only one boy and therefore there must be 3 girls, for a total of 4

experimentx · Answer

so quite opposite than the last illustration huh?

anonymous · Answer

then 
$$\frac{18\times 3+x}{4}=17$$
$$54+x=68$$
$$x=14$$

anonymous · Answer

so the lone boy scored 14 points. since it doesn't matter for the problem how many there are, this is the answer

anonymous · Answer

I got it now. Thank you

ashtorah13 · Answer

but why do you multiply 18 and 3?