Question

SchoolMath 5 points


The sum of weights of an iron and of a copper piece is 1280 grams.The volume of a copper piece is twice that of iron piece.If weight of 1 cubic centimeter of iron is 7.8grams and that of copper is 8.9grams.Find the volume of each?

Answer 1

Answer:

Let Pc be density of copper and Pi the density of iron

Pc * Vc + Pi * Vi = 1280      where Vc and Vi are the volumes

Pc * 2 Vi + Pi * Vi = 1280     since Vc = 2 Vi

Vi * (2 Pc + Pi) = 1280

Vi = (2 * 8.9 + 7.8) = 1280

Vi = 50    and then Vc = 2 Vi = 100

Check:  50 * 7.8 + 100 * 8.9 = 1280