Answer:
Equation is 42t
So,
t=12
According to equation
Put value of t
=42(12)
=504
So 2nd option is correct.
Answer:
2nd
Step-by-step explanation:
using the quadric formula

do the math and you get the second one.
{-1/3,5/2}
Answer:
D
Step-by-step explanation:
So it'd be
28=3s+4
28-4=3s
24=3s
24/3=3s/3
8=2
Answer:
And rounded up we have that n=421
Step-by-step explanation:
We know that the sample proportion have the following distribution:

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by
and
. And the critical value would be given by:
The margin of error for the proportion interval is given by this formula:
(a)
And on this case we have that
and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
We assume that a prior estimation for p would be
since we don't have any other info provided. And replacing into equation (b) the values from part a we got:
And rounded up we have that n=421