Answer:
The height of the pile is increasing at the rate of 
Step-by-step explanation:
Given that :
Gravel is being dumped from a conveyor belt at a rate of 20 ft³ /min
i.e 
we know that radius r is always twice the diameter d
i.e d = 2r
Given that :
the shape of a cone whose base diameter and height are always equal.
then d = h = 2r
h = 2r
r = h/2
The volume of a cone can be given by the formula:




Taking the differentiation of volume V with respect to time t; we have:


we know that:

So;we have:



The height of the pile is increasing at the rate of 
The answer to your question is X= 11
The first four-term of the sequence is found by the given equation
is given as 144, 36, 9, and 9/4.
<h3>What is a sequence?</h3>
A sequence is a list of elements that have been ordered in a sequential manner, such that members come either before or after.
The given equation will be

And

For n = 4, we have

For n = 3, we have

For n = 2, we have

More about the sequence link is given below.
brainly.com/question/21961097
Simply take the numerator (3) and denominator (7) and add them together.
3+7 = 10, which means that the ratio will provide parts that are in multiples of 10 depending on the total
so take 10x = 800
x = 80.
Then multiply this by the numerator and denominator
3*80/7*80 = 240/560.
3x600= 3 x 6 hundreds
= 18 hundreds
<span>= 1,800</span>