So she reads for 5 hours every day for 15 days, how many hours is that? well is just 5*15, or 75 hours.
so, she reads 900 pages in 75 hours, how many pages does she do in 1 hour?
Answer:
The first step is to find the volume of the two hemispheres.
Step-by-step explanation:

Since the 2 hemispheres have the same radius, we can simply find the volume of a sphere.
Volume of sphere


Volume of solid
= volume of cylinder -volume of 2 hemispheres
Let's find the volume of the cylinder.

Volume of cylinder


Thus, volume of solid




How much is the mass of one rock?
Do that first.
I hoped I helped:)
.4 and .40 are indeed the same amount.
We usually drop the 0 in the 100'ths place when it is not necessary for indicating money or solving a problem with 2 decimals.
Also realize that .400 .4000 etc are all the same as well.