homework help

coockies are packed  in 2 kinds of boxes : big and small. the number of coockies in a small box is half of the number of coockies in the big box. how many coockies there are in every box if 3 big boxes and 5 small boxes have 165 coockies together 

OK.....let's call the number of cookies in the small box "x."  And since the number of cookies in the big box is twice as many, let's call that "2x."

So ....  the number of small boxes times the number of cookies in each plus the number of big boxes times the number of cookies in each equals 165.  Mathematically, we have

5(x) + 3(2x) = 165   So we have

11x = 165  Divide by 11  and we get

x = 15    So........that's the number of cookies in the small box

And since the big boxes hold twice as many, there must be 30 in each one of them. 

And that's it