Amount Produced

[Guest]

Determine number of glass marbles produced from 15 lbs. of material, allowing 5% for waste. The marbles are 1.5 in. in diameter.

Volume of sphere = 4/3 * pi * r^3.

1.333 * 3.1416 * .625 * .625 * .625 = 1.022 cu. in.

Not sure from this point.

[Guest]

1.333 * 3.1416 * .625 * .625 * .625 = 1.022 cu. in.

Error in post; should be: 1.333 * 3.1416 * .75 * .75 * .75 = 1.766 cu. in.

Also, glass weighs .0945 lbs. / cu. in. ; omitted by mistake.

[Guest]

5% waste so 95% is used for marbles
you have found the volume of 1 marble
each cu ins weighs 0.0945 lbs so multiply the volume by 0.0945 to get weight of a marble
divide this marble weight into what is 95% of 15 lbs to get how many marbles

[Guest]

1.766 * 0.0945 = .1668 lbs. (weight of 1 marble)

.95 * 15 = 14.25 lbs. (amt. of material)

14.25 / .1668 = 85.43 = 85 marbles.

Where am I incorrect ?

[Guest]

Yes, correct

[Guest]

Thanks.