Answer:
1000
Step-by-step explanation:
I got D.
There's a few ways to solve it; I prefer using tables, but there are functions on a TI-84 that'll do it for you too. The logic here is, you have a standard normal distribution which means right away, the mean is 0 and the standard deviation is 1. This means you can use a Z table that helps you calculate the area beneath a normal curve for a range of values. Here, your two Z scores are -1.21 and .84. You might notice that this table doesn't account for negative values, but the cool thing about a normal distribution is that we can assume symmetry, so you can just look for 1.21 and call it good. The actual calculation here is:
1 - Z-score of 1.21 - Z-score .84 ... use the table or calculator
1 - .1131 - .2005 = .6864
Because this table calculates areas to the RIGHT of the mean, you have to play around with it a little to get the bit in the middle that your graph asks for. You subtract from 1 to make sure you're getting the area in the middle and not the area of the tails in this problem.
Answer: 1/70
Step-by-step explanation:
This is a question that can also be interpreted as what is the probability of having the first number of a phone number to be 8 and the last number of the phone number to also be 8. This answer gives the fraction of the phone numbers that starts with 8 and end with 8.
Since three numbers (0,1,2) cannot start a phone number and we are left to pick from 7 numbers,
then the probability of figure "8" starting phone number = 1/7
Since all 10 numbers can possibly end a phone number,
then the probability of having figure "8" as the last digit of a phone number = 1/10
Hence probability of having "8" as the first and last digit of a phone number = fraction of total telephone numbers that begin with digit 8 and end with digit 8 = 1/7 × 1/10 = 1/70.
Triangle has 180 degrees:
180=2m-3+m+4+3m+5
Combine like terms
180 = 6m+6
Subtract 6 from 180
174=6m
Divide by 6
m=29
Brainliest if that helped, please :)