Answer:
Step-by-step explanation:
Given the quadratic equation:
To solve it, we follow these steps:
1. Rearrange the terms to one side of the equation:
2. Utilize the Quadratic formula
.
In this case, we can identify that:
Then, substituting these values into the Quadratic formula gives us the following solutions:
The last part of the question is asking;
What was the total amount spent by all (99.7%) students on textbooks in a semester?
Response:
almost all (99.7%) of the students spent between $165 and $315 on textbooks in a semester.
Stepwise clarification:
The standard deviation rule informs that for normally distributed data, approximately 99.7% of observations fall within three standard deviations from the mean.
In this case, we have the given mean as 240, and standard deviation as 25
Thus, calculating three standard deviations below the mean: Mean - 3(standard deviation)
equals 240 - (3 × 25)
yielding 240 - 75 = 165
Now, for three standard deviations above the mean: Mean + 3 (standard deviation) = 240 + (3 × 25)
equals 240 + 75 = 315
Therefore, nearly all (99.7%) of the students spent between $165 and $315 on textbooks in a semester.
