<span>When order does not matter you use what is called n choose k formula
n!/(k!(n-k)!) where n is the number of things to choose from and k is the number of choices made, in this case:
20!/(4!(20-4)!)=4845</span>
3 plus 1 equals 4 so its 4/6. When you simplify it the answer is 2/3
REVISED ANSWER.
In the picture, I have drawn on the example given. the RC and PD are the same because They are across from each other perfectly. So the answer is still PD=400m but if there can be two answers then I would have to say another possiblity would be 200m for the diameter of the pond. The wording of this problem is tricky and the picture can throw you off a bit but I did my best to answer properly here.
So if you could mark brainliest that would be awesome.
Answer:
p(-10) = 31
Step-by-step explanation:
Plug in -10 as x into the equation, and solve
p(x) = x + 41
p(-10) = -10 + 41
p(-10) = 31