Answer: 1.25
Step-by-step explanation:
Given: A college-entrance exam is designed so that scores are normally distributed with a mean = 500 and a standard deviation = 100.
A z-score measures how many standard deviations a given measurement deviates from the mean.
Let Y be a random variable that denotes the scores in the exam.
Formula for z-score =
Z-score =
⇒ Z-score =
⇒Z-score =1.25
Therefore , the required z-score = 1.25
Answer:
Audrey can afford 4 hours of lesson.
Step-by-step explanation:
Given that:
Amount Audrey has to spend = $111
Cost of racket = $55
Cost per lesson = $14
Let,
y be the total cost
x be the number of hours
According to given statement;
y = 14x + 55
111 = 14x + 55
111 - 55 = 14x
14x = 56
Dividing both sides by 14
Hence,
Audrey can afford 4 hours of lesson.
There are 150 students in Hannah's school.
Sum of books donated by the students =b.
Average books donated by each student =
It is given Hannah donated 3 times as many books each student donated.
Number of books donated by Hannah=
The expression of the number of books donated by Hannah=