The answer is 90 different pairs.
So if there are 10 topics and each will get 9 pairings , so the over all pairs you will get is 90.
I'm pretty sure you just answered your own question, (no hate), but I'm going to take a guess and say 2 hours??
Answer:

Therefore the probability that a randomly selected student has time for mile run is less than 6 minute is 0.0618
Step-by-step explanation:
Normal with mean 6.88 minutes and
a standard deviation of 0.57 minutes.
Choose a student at random from this group and call his time for the mile Y. Find P(Y<6)


y ≈ normal (μ, σ)
The z score is the value decreased by the mean divided by the standard deviation

Therefore the probability that a randomly selected student has time for mile run is less than 6 minute is 0.0618
<u>Given</u>:
Given that the circle with center O.
The radius of the circle is OB.
The chord of the circle O is PQ and the length of PQ is 12 cm.
We need to determine the length of the segment PA.
<u>Length of the segment PA:</u>
We know that, "if a radius is perpendicular to the chord, then it bisects the chord and its arc".
Thus, we have;

Substituting the value PQ = 12, we get;


Thus, the length of the segment PA is 6 cm.
Hence, Option d is the correct answer.
We have 4 deliveries ( 12 1/3 , 8 3/4, 17 2/8 and 23 2/3 miles ) and also the final delivery : 10 5/10 miles = 10 1/2 miles.
We have to add up all the deliveries and to divide the result by 5:
( 12 1/3 + 8 3/4 + 17 1/4 + 23 2/3 + 10 1/2 ) : 5 =
= 72 1/2 : 5 = 72.5 : 5 = 14.5 = 14 1/2
Answer: The average distance for all segments of this trip is 14 1/2 miles.