If white balls have a mass of 5.0 grams and black balls have a mass of 2.0 grams, in a box containing white and black balls with $\frac{2}{3}$ $2/3$ of the balls being white, what is the average mass of a single ball in this box?

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Answer 1 · 2015-09-02T11:07:06

Average mass (per ball) $= 4.0$ $= 4.0$ g.

If $\frac{2}{3}$ $2/3$ of the balls are white

then we could group the balls into groups of 3 with 2 white balls and 1 black ball in each group.

Each group would weight $2 \times 5.0 g + 1 \times 2.0 g = 12.0 g$ $2xx5.0" g" + 1xx2.0 " g "= 12.0 " g"$

and since there are $3$ $3$ balls in each group,
the average weight would be $\frac{12.0 g}{3} = 4.0 g$ $(12.0" g")/3 = 4.0 " g"$

If white balls have a mass of 5.0 grams and black balls have a mass of 2.0 grams, in a box containing white and black balls with 232/3 of the balls being white, what is the average mass of a single ball in this box?