Answer:
I'm pretty sure it's a
Step-by-step explanation:
A:41
B:27
C:38
D:40
The diameter is given which is 13.5feet and radius is half of diameter. Therefore radius = 6.75 feet.
Slant height = 16.8 feet
The formula of surface area of cone is

Correct option is C
Obviously, it's not rational, because it's the sum of two square roots, so cancel out A and B right away.
If we solve it
sqrt (18) + sqrt (2)
= sqrt (9*2) + sqrt (2)
= 3 sqrt (2) + sqrt (2)
= 4 sqrt (2)
D :D
The number of possible combinations is given by
... C(18, 3) = 18!/(3!(18-3)!) = 18·17·16/(3·2·1) = 816 . . . . possible combinations
_____
There are 18 ways to choose the first one; 17 ways to choose the second one, and 16 ways to choose the 3rd one. The same 3 students can be chosen in any of 3! = 6 different orders, so the product 18·17·16 must be divided by 6 to get the number of possible combinations in which order doesn't matter.