Answer:
i think so?
Step-by-step explanation:
Answer:
2 hours
Step-by-step explanation:
Train B's speed: 4/3 × 60 = 80
Combined speed = 80 + 60 = 120
Time = 240/120 = 2
Answer:
Do u mind reposting ur question-? I dont quite undersatnd what u're asking ;-;
Step-by-step explanation:
We have been given that the distribution of the number of daily requests is bell-shaped and has a mean of 38 and a standard deviation of 6. We are asked to find the approximate percentage of lightbulb replacement requests numbering between 38 and 56.
First of all, we will find z-score corresponding to 38 and 56.


Now we will find z-score corresponding to 56.

We know that according to Empirical rule approximately 68% data lies with-in standard deviation of mean, approximately 95% data lies within 2 standard deviation of mean and approximately 99.7% data lies within 3 standard deviation of mean that is
.
We can see that data point 38 is at mean as it's z-score is 0 and z-score of 56 is 3. This means that 56 is 3 standard deviation above mean.
We know that mean is at center of normal distribution curve. So to find percentage of data points 3 SD above mean, we will divide 99.7% by 2.

Therefore, approximately
of lightbulb replacement requests numbering between 38 and 56.
The formula for a discriminant is b^2-4ac
so, (-7)^2 -4(3)(6) simplifies to 49-72 which equals -23