This is a round robin style tournament. Given that there are 25 people, and order doesn't matter meaning that the combination AB is equivalent to BA you must use the choose formula.
Thus the answer should be 25C2 or
<em>25! / [(25-2)! * 2!] = 300</em>
Answer:
Step-by-step explanation:
From the given information; Let's assume that R should represent the set of all possible outcomes generated from a bit string of length 10 .
So; as each place is fitted with either 0 or 1

Similarly; the event E signifies the randomly generated bit string of length 10 does not contain a 0
Now;
if a 0 bit and a 1 bit are equally likely
The probability that a randomly generated bit string of length 10 does not contain a 0 if bits are independent and if a 0 bit and a 1 bit are equally likely is;

so ; if bits string should not contain a 0 and all other places should be occupied by 1; Then:
; 

10+8h=66
minus 10 both sides
8h=56
divide both sides by 8
h=7
worked 7 hours