Answer:
a)
And rounded up we have that n=4906
b) For this case since we don't have prior info we need to use as estimatro for the proportion 
And rounded up we have that n=6724
Step-by-step explanation:
We need to remember that the confidence interval for the true proportion is given by :
Part a
The estimated proportion for this case is 
Our interval is at 90% of confidence, and the significance level is given by
and
. The critical values for this case are:
The margin of error for the proportion interval is given by this formula:
(a)
The margin of error desired is given
and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
Replacing we got:
And rounded up we have that n=4906
Part b
For this case since we don't have prior info we need to use as estimatro for the proportion 
And rounded up we have that n=6724
First 1/5 is equivalent to 20% so to get 20% of both of them multiply by .2. so 400×.2=80 and 90×.2=18
Answer:
there are 6/8 in 3/4
Step-by-step explanation:
if you want to change the denominator of the fraction, you must find the multiple of it,
(3/4) x 2 is 6/8
so you have 6 x (1/8) thats the same 6/8
3/4 is the minimum simplification, if you want to find the same fraction but with other denominator, you have to multiply 3/4 for any number, to do this you have to multiply the numerator and the denominator