An Alloy A contains copper and tin in a ratio of 3:5 by weight . Another alloy B contains tin and zinc in the ratio of 3:7 by weight . Find the ratio of copper : tin : Zin in a new alloy containing equal weights of alloys A and B .
My attempt .
Copper : Tin = $ 3 : 5 $
Tin : Zinc = $ 3 : 7 $
I tried to make the tin ratio the same .
$ 5 X 3/5 = 3 $
Then use $ 3/5 $ and multiply the copper in alloy A .
$ 3 X 3/5 = 1.8 $
This is give me
Copper : Tin : Zinc = $ 1.8 : 3 : 7 = 9 : 15 : 35 $
However my answer is wrong . Can I get help on why ? Thanks !