Answer:
Step-by-step explanation:
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+ 
the LCD of the denominators is 168y , then
← distribute and simplify numerator
= 
=
Answer:
2/3 chance
Step-by-step explanation:
You want to find numbers less than 5, so there are 4 numbers you can use. 4 out of 6 numbers possible is 4/6, or 2/3.
44x is the way the points are calculated. In order to find out the amount of questions there needs to be a constant, 10 which represents the number of wrong questions, and a variable, x which represents the number of correct questions. You have to know that if wrong questions were counted, he would have 440 points just for the 10 wrong questions. Next you have to add the amount of correct questions and their corresponding points. The numbers that you get should be put together with the wrong questions. The points for the wrong questions don't count but the questions do. When you find the number, (I don't know what it is so I will use x but you will have to find out what it is) you will add x, the number of correct questions to the 10 incorrect questions and then you will have 10+x for the questions. You will need to use 44x to find out the number of points and once you have done that, you use this equation to average the points over the total questions: 44x/10+x
(2)^4-2(2)^3-6(2)^2+5
16-64-144+5
-187
The 68-95-99.7 rule tells us 68% of the probability is between -1 standard deviation and +1 standard deviation from the mean. So we expect 75% corresponds to slightly more than 1 standard deviation.
Usually the unit normal tables don't report the area between -σ and σ but instead a cumulative probability, the area between -∞ and σ. 75% corresponds to 37.5% in each half so a cumulative probability of 50%+37.5%=87.5%. We look that up in the normal table and get σ=1.15.
So we expect 75% of normally distributed data to fall within μ-1.15σ and μ+1.15σ
That's 288.6 - 1.15(21.2) to 288.6 + 1.15(21.2)
Answer: 264.22 to 312.98
