Answer:
Option D) $275
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = $235
Standard Deviation, σ = $20
We are given that the distribution of amount of money spent by students is a bell shaped distribution that is a normal distribution.
Formula:

We have to find the value of x such that the probability is 0.975
Calculation the value from standard normal z table, we have,

Approximately 97.5% of the students spent below $275 on textbook.
Answer:
Put another dot on 79
Step-by-step explanation:
Because the plot shows that 79 must have 4 dot.So you need to add one more dot
X+a=b
you want to isolate x so subtract a from both sides
x=b-a
0.88. you can simply see this by using the right use of the data