To find the value of x let's make the situation a bit easier
3x+10+70=180
3x+80=180
3x=180-80
3x=100
x = about 33.33
The answer should be 26 hours
Answer:
50 pages per hour
Step-by-step explanation:
Using the normal distribution, it is found that she scores less than 128 in 28.1% of her games.
<h3>Normal Probability Distribution</h3>
The z-score of a measure X of a normally distributed variable with mean
and standard deviation
is given by:

- The z-score measures how many standard deviations the measure is above or below the mean.
- Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.
In this problem, the mean and the standard deviation are given, respectively, by
.
The proportion of games in which she scores less than 128 is the <u>p-value of Z when X = 128</u>, hence:


Z = -0.58
Z = -0.58 has a p-value of 0.281.
She scores less than 128 in 28.1% of her games.
More can be learned about the normal distribution at brainly.com/question/24663213
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Black keys=b
white keys=w
b+w=88|·9
w:b=13/9⇒9w=13b
9b+9w=792
13b+9b=792
22b=792|:22
b=36 keys
w=88-36
w=52 keys