The group lose 8.8 pounds per day. For a detailed calculation, please refer to the attachment.
Answer:
C
Step-by-step explanation:
Given

Divide each term on the numerator by 4x
=
+
+ 
=
+ 2 + 
Answer:
A
Step-by-step explanation:
Calculation seems correct to me, with d the distance and h the height of the plane, and i got the same value. Closest value is A tho, so i'd stick with it.
If you want to be pedantic about it, you can always divide the heigth by each value, and get the inverse tangent of each value. With A you get 17.995 which seems the best value you get
I assume you're looking for the number:
0.5n + 9 = 21
- 9
0.5n = 12
÷ 0.5
n = 24
So the beginning number is 24, hope this helps!