Answer:
The sample size required is 910.
Step-by-step explanation:
The confidence interval for population proportion is:

The margin of error is:

Given:

The critical value of <em>z</em> for 90% confidence level is:
*Use a standard normal table.
Compute the sample size required as follows:

Thus, the sample size required is 910.
Answer:
A
Step-by-step explanation:
It is making me add 20 characters to my answer so ignore this :)
Answer: C. 
Step-by-step explanation:
Given: Box contains 8 green balls and 4 purple balls.
Total balls = 8+4 = 12
event 1 = first picking green ball
event 2 = second picking purple balls.
As first ball was replaced, that means both events are independent.
Probability that you have selected a green ball and then a purple ball = P(purple ball )
Formula for probability = 
Probability of selecting a purple ball (second pick)= 

The required probability
, so C is correct option.
To convert 15 ft to centimeters you have to multiply 15 x 30.48, since 1 ft is 30.48 cms
So, if you want to calculate how many centimeters are 15 feet you can use this simple rule.
Answer:
The towel costs 110 rupees
Step-by-step explanation:
Let n be napkins, and t be towels. Then:
6n+t=200
and
n=t-95
So:
6(t-95)+t=200
7t-570=200
7t=770
t=110....................