Answer:
a
Step-by-step explanation:
Answer:
atleast 385
Step-by-step explanation:
Given that an electrical power company is looking to expand into a new market. Before they commit to supplying the new area with electricity, they would like know the mean daily power usage for homes there.
Population std deviation = 
Sample size =
STd error of sample mean = 
Margin of error for 95% would be Critical value ( std error)
Here since population std dev is known we can use Z critical value= 1.96

Sample size should be atleast 385
Answer:
x=18
Step-by-step explanation:
21:28=x:24
1. rewrite: 21/28 = x/24
2. simplify: 3/4=x/24
3. multiply 24 to both sides: x=18