A single pen weighs 5.2 g. A box full of pens weighs 751.8 g. The empty box weighs 3 g. How many pens ?

Question

A single pen weighs 5.2 g. A box full of pens weighs 751.8 g. The empty box weighs 3 g. How many pens ?

Answer 1

to confirm  144 pens

Answer 2

Exactly how Scott said it.

781.8g minus the weight of the box 3g = 778.8g

The total mass of the pens is therefore 778.8, so divide that by 5.2g and see how many pens there are.

Just for general knowledge: The only way you'd get a decimial answer when you divide the total mass by 5.2g (the weight of the pens) is if the pens weren't whole numbers of pens, i.e. half a pen or a third of a pen.

Answer 3

751.8g - 3 g = 748.8g (total mass of pens)

748.8g / 5.2g = 144 pens