Answer:
B. $3100
Step-by-step explanation:
if he's going to pay for his friend. The least expensive dinner menu is $725, for him and his friend it would be $1450. Then for the movie tickets it's $8.00 each, $16.00. $1450+$16.00=$30.50. Round that to the closest whole number, $3100.
Answer:
The rate of change in surface area when r = 20 cm is 20,106.19 cm²/min.
Step-by-step explanation:
The area of a sphere is given by the following formula:

In which A is the area, measured in cm², and r is the radius, measured in cm.
Assume that the radius r of a sphere is expanding at a rate of 40 cm/min.
This means that 
Determine the rate of change in surface area when r = 20 cm.
This is
when
. So

Applying implicit differentiation.
We have two variables, A and r, so:



The rate of change in surface area when r = 20 cm is 20,106.19 cm²/min.
Highest common factor of 56&65 is 1
I believe the first answer is c