Help me please ! HSHWJWJWODO
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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 :-
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 :
Now, the probability of runners who finish in under 19 minutes by using standard normal distribution table :-
Hence, the approximate proportion of runners who finish in under 19 minutes = 0.0228
Given:
The ratio of red and blue cubes is 4:7.
After adding 10 more red cubes the ratio of red and blue cubes is 6:7.
To find:
The number of blue cubes.
Solution:
The ratio of red and blue cubes is 4:7.
Let the number of red and blue cubes be 4x and 7x respectively.
After adding 10 more red cubes.
Number of red cubes = 4x+10
Then, the ratio of red and blue cubes is 6:7.
Divide both sides by 14.
Now,
Number of blue cubes in the bag is
Therefore, the number of blue cubes is 35.