Y = -2 x - 9
3 x - 4(-2 x - 9 ) = -8
3 x + 8 x + 36 = - 8
11 x = - 44, x = - 4
y = 8 - 9 , y = -1
This is a unique solution, the system is independent.
x/20 = 21/14 (similar proportions)
x/20 = 3/2 (simplify by canceling out a factor of 7)
x = 30
Answer:
34 songs
Step-by-step explanation:
120min/3.53 = 33.99
Answer:
So then the minimum sample to ensure the condition given is n= 38
Step-by-step explanation:
Notation
represent the sample mean for the sample
population mean (variable of interest)
represent the population standard deviation
n represent the sample size
ME = 4 the margin of error desired
Solution to the problem
When we create a confidence interval for the mean the margin of error is given by this formula:
(a)
And on this case we have that ME =4 and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
The critical value for 96% of confidence interval now can be founded using the normal distribution. The significance is
. And in excel we can use this formula to find it:"=-NORM.INV(0.02;0;1)", and we got
, replacing into formula (b) we got:
So then the minimum sample to ensure the condition given is n= 38