Answer: 0.0228
Step-by-step explanation:
Given : The mean and the standard deviation of finish times (in minutes) for this event are respectively as :-
![\mu=30\\\\\sigma=5.5](https://tex.z-dn.net/?f=%5Cmu%3D30%5C%5C%5C%5C%5Csigma%3D5.5)
If the distribution of finish times is approximately bell-shaped and symmetric, then it must be normally distributed.
Let X be the random variable that represents the finish times for this event.
z score : ![z=\dfrac{x-\mu}{\sigma}](https://tex.z-dn.net/?f=z%3D%5Cdfrac%7Bx-%5Cmu%7D%7B%5Csigma%7D)
![z=\dfrac{19-30}{5.5}=-2](https://tex.z-dn.net/?f=z%3D%5Cdfrac%7B19-30%7D%7B5.5%7D%3D-2)
Now, the probability of runners who finish in under 19 minutes by using standard normal distribution table :-
![P(X](https://tex.z-dn.net/?f=P%28X%3C19%29%3DP%28z%3C-2%29%3D0.0227501%5Capprox0.0228)
Hence, the approximate proportion of runners who finish in under 19 minutes = 0.0228
Answer:
Step-by-step explanation:
28 is the LCM of 4 and 7 as 4*7 = 28
The first blank is propyl 4 and the second is 2 (this is what I can tell if AB was 9 then PQ 3, so practically dividing by 3)
Answer:
![\frac{10}{x+2} = \frac{3}{x-2}](https://tex.z-dn.net/?f=%5Cfrac%7B10%7D%7Bx%2B2%7D%20%3D%20%5Cfrac%7B3%7D%7Bx-2%7D)
Step-by-step explanation:
The 10 represents the speed traveling downsteam while the 3 represents speed upstream. Downstream you have the help of the current, so it would be x + 2, upstream you are working against the current so it would be x - 2.