Answer:
The answer is 
Step-by-step explanation:
Assuming the snowball is a perfect sphere, then if A denotes the surface area and D the diameter then:

Differentiating wrt r we have:

We are told that
and we want to find 
By the chain rule we have:

∴
∴
When D=10 then

The sign (-) shows that the D is decreasing.
Answer:
120 trees
Step-by-step explanation:
4x10=40
40x3=120
120 trees will be planted
<u>Answer:</u>
0.45m + 33
<u>Step-by-step explanation:</u>
We are instructed to multiply the number the number of minutes Mr. Frotout spent on long distance calls by 0.45 the long distance rate then add 33 the flat monthly charge.
Assuming the number of long minutes spent on long distance calls by Mr. Frotout to be
, we can express the given situation as follows:
