80 because tens place is two over from the right
For number 3.
You add 8 to both sides as you need to separate the variable
4x-8=32
+8 +8
4x=32
now divide 32 by 4
x=8
for number 4
you use pemdas to multiply the parenthisis
2(x-5)=-20
(2•x)-(2•5)
2x-10=-20
then add 10 to both sides
2x-10=-20
+10 +10
2x=10
divide 10 by two
x=5
The answer is B: <span>choosing five CDs where not all of them are pop</span>
If the mean is 20.8, one standard deviation each way is adding and subtracting 3.1, so 17.7 and 23.9 (68% of values)
Two standard deviations adding and subtracting 3.1*2 = 6.2, or 14.6 and 27.
Three standard deviations is 11.5 and 30.1
So we have
11.5 - 14.6 - 17.7 - 20.8 - 23.9 - 27 - 30.1
Going left to 11.5 is 3 standard deviations out, so 99.7/2 = 49.85%
Going right to 27 is 2 standard deviations out, so 95/2 = 47.5%
Add those two % to get 97.32%
This is hard to do without a picture so I hope that helps!
