We must find UNIQUE combinations because choosing a,b,c,d... is the same as d,c,b,a...etc. For this type of problem you use the "n choose k" formula...
n!/(k!(n-k)!), n=total number of choices available, k=number of choices made..
In this case:
20!/(10!(20-10)!)
20!/(10!*10!)
184756
Answer:
x
=
(23
+
√
497 /
8)
, (23
−
√
497 /8)
x=5.66168710
Step-by-step explanation:
im too lazy. use math-way
I would say A (7) but I’m not 100% sure.