Answer:

-10416
Step-by-step explanation:
a = 4
r = -5
geometric series: 
Determine which term = -12500:








Using geometric sum series formula: 
Therefore, 
Answer:
AE = 19 and <EDC = 59
Step-by-step explanation:
i am almost positive that those are both right
Answer:
Well since we don't know what X or Y is, then we can't answer this question.
Step-by-step explanation:
It wouldn't let me post the answer. See images for the answer and explanation
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