Answer:
interval=(15.085,14.9515)
Step-by-step explanation:
Table:
CI Z
85% 1.440
90% 1.645
95% 1.960
In order to find the interval/estimate of hours per week students study we consider the formula given below:
Interval=X±
where:
X is the mean hours
Z is the value from Z distribution table of Confidence Interval
n is the sample size of students
S is the standard deviation
X=15, Z=1.645, S=2.3hours, n=78
Interval=15±
Interval=15±0.0485
interval=(15.085,14.9515)
Answer:
37/66
Step-by-step explanation:
To have removed at most 2 pennies out of 4 coins, you could have either selected 4 nickels, 3 nickels, and 1 penny or 2 nickels and 2 pennies.
There is only one way to select 4 nickels: 6/11 x 5/10 x 4/9 x 3/8 = 1/22
There are four ways to select 3 nickels and 1 penny; each way is: 6/11 x 5/10 x 4/9 x 5/8 = 1/66
4 x 1/66 = 2/33
There are six ways to select 2 nickels and 2 pennies; each way is: 6/11 x 5/10 x 5/9 x 4/8 = 5/66
6 x 5/66 = 5/11
Adding these probabilities: 1/22 + 2/33 + 5/11 = 37/66
Answer:
Step-by-step explanation:
Plan A = 30 +0.15x
Plan B = 16 +0.20x
30+0.15x = 16+0.20x
subtract 16 from each side
14 +0.15x = 0.20x
subtract 0.15x from each side
14=0.05x
x = 14/0.05 = 280 minutes
280*0.15 = 42 +30 = $72
280 * 0.20 = 56 +16 = 72
280 minutes and cost $72 each
<h2>
Greetings!</h2>
Answer:
x = 5 and y = -2
Step-by-step explanation:
Here you have given what y is equal to, this means you can sub this into the first equation:
3x - 2(x - 7) = 19
Expand the brackets:
-2 * x = -2x
-2 * -7 = 14
3x -2x +14 = 19
Move the +14 over to the other side making it a -14:
3x - 2x = 19 - 14
3x - 2x = 5
3x - 2x = x
So x = 5
Now sub this into the first equation:
3(5) - 2y = 19
15 - 2y = 19
Move the -2y over to the other side making it a +2y, and move the +19 over to the other side making it a -19:
15 - 19 = 2y
-4 = 2y
Divide both sides by two:
y = -2
So x = 5 and y = -2
<h2>Hope this helps!</h2>