B
AKA 2
I have Khan Acadamy!!
Your welcome!
Answer:
a = - 5, a = - 3
Step-by-step explanation:
Given
a² + 8a + 15 = 0 ← in standard form
(a + 3)(a + 5) = 0 ← in factored form
Equate each factor to zero and solve for a
a + 3 = 0 ⇒ a = - 3
a + 5 = 0 ⇒ a = - 5
Answer:
A task time of 177.125s qualify individuals for such training.
Step-by-step explanation:
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by

After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X. Subtracting 1 by the pvalue, we This p-value is the probability that the value of the measure is greater than X.
In this problem, we have that:
A distribution that can be approximated by a normal distribution with a mean value of 145 sec and a standard deviation of 25 sec, so
.
The fastest 10% are to be given advanced training. What task times qualify individuals for such training?
This is the value of X when Z has a pvalue of 0.90.
Z has a pvalue of 0.90 when it is between 1.28 and 1.29. So we want to find X when
.
So




A task time of 177.125s qualify individuals for such training.
1/5 divided by 5/7 is 7/25
1/5 ÷ 7/5 = 7/25
Your answer is 7/25