Answer:
140m
Step-by-step explanation:
3/4 = .75
x/.7 = 150/.75
multiply both sides by .7
x = 150/.75 * .7
x = 140m
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
Assuming that's a 40 minutes a lesson the minutes the tennis teacher teaches in a week is 800 minutes
Answer:
B.
Step-by-step explanation:
That would be B.
8/3 + √(-7/3) :- because it consists of a real part ( the 8/3) and an imaginary part √(-7/3).
The √(-7/3) is usually written as √(7/3)i where i is √-1, so the complex number is 8/3 + √(7/3)i.