Part a: Option D 18 feet per second
Part b: increasing
Solution:
Height 
Part a: To find the average rate of change for h(t) between t = 0 and t = 2.
Substitute t = 0 in h(t).

h(0) = 3
Substitute t = 2 in h(t).
h(2) = 39
Average rate of change formula:

Here, a = 0 and b = 2.



= 18
Average rate of change = 18 feet per second
Option D is the correct answer.
Part b:
This means height of the ball is increasing for 0 < x < 2.
Answer: x= 21.6
Step-by-step explanation:
12^2 + 18^2 =x^2
144 + 324 =x^2
468 = x^2
c= 21.633
To the nearest tenth place is c= 21.6
Packet of 12 pencils = p
Packet of 30 rulers = r
p = £2.15
r = £6.00
£35 = 4r + xp
£35 = 4(£6.00) + x(£2.15)
£35 = £24 + £2.15x
£11 = £2.15x
x = 5.12
Since she can buy 5.12 packets of pencils, it is equal to 5 packets of pencils.
Answer:
The answer is B
Step-by-step explanation: