I think answer is 90•13.50=103.5 i am not quite sure about it but..
Answer:
Look at the photo below for the answer.
:)
When an spherical balloon volume is increasing at the rate of
then the diameter of the balloon is increasing 
How can we find the rate of change of balloon's diameter ?
The volume of a spherical balloon is 
In form of diameter we can write as

Now we will differentiate both sides wrt to
we get

Given in the question 
thus when we substitute the values we get

Learn more about the differentiation here:
brainly.com/question/28046488
#SPJ4
1.) First plug in the values for m and A:

--> 
Isolate b: 
b = 1999
So your answer is the first option.
2.) Admission costs $5.25, so even if you don't go on any rides, you will still have to pay $5.25. This means that for this problem, 5.25 will be the b value. If each ride costs $2.50, then this means it is $2.50x for the cost of x rides. The total cost will then be
.