A hot air balloon holds 4,328 cubic meters of helium. The density of helium is 0.1785 kilograms per cubic meter. How many kilograms of helium does the balloon contain, rounded to the nearest tenth of a kilogram?

A. 3,747.9 kg
B. 3,875.3 kg
C. 772.5 kg
D. 4,383.2 kg

Question

A hot air balloon holds 4,328 cubic meters of helium. The density of helium is 0.1785 kilograms per cubic meter. How many kilograms of helium does the balloon contain, rounded to the nearest tenth of a kilogram?

A. 3,747.9 kg
B. 3,875.3 kg
C. 772.5 kg
D. 4,383.2 kg

anonymous · Answer

@phi @magbak @mathslover @KingGeorge @ajprincess

mathslover · Answer

Use the formula of density here :

$\rho = \cfrac{mass}{volume}$ 

where $\rho$ ( pronounced as rho) is the density of the substance (here substance is Helium)

Given to you that density of helium in the balloon : $\rho _ {He} = 0.1785 kg m^{-3}$ 

And given that volume of Helium gas in the balloon = 4,328 $m^3$

mathslover · Answer

So, just put the values :

$\rho _{He} = \cfrac{m_{He}}{V_{He}}$

anonymous · Answer

I still dont understand...

mathslover · Answer

What is given to you in the question?

anonymous · Answer

The amount of helium in the balloon and the density.

mathslover · Answer

Right. So, it is actually volume of helium gas and the density

Since, density = mass/ volume

So, mass = density * volume

mathslover · Answer

Just put the given values.

anonymous · Answer

4,328/0.1785 = 24,246...

mathslover · Answer

It is multiplication, not division .

mathslover · Answer

That is 

Mass = Volume * Density = 4328 * 0.1785

anonymous · Answer

Got it, Thank you!

mathslover · Answer

You're very welcome :)

shaw74 · Answer

the answer is c

anonymous · Answer

4328 * 0.1785 = 772.548
So C is correct!