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Answer: 68
Step-by-step explanation:
As per given , we have
Population standard deviation : 
Critical value for 90% confidence interval =
Margin of error : E= 0.8 milligrams
The formula to find the sample size is given by :-

i.e. 

Hence, the limnologist must analyze 68 samples.
1.26 . 15 percent in a decimal would be .15 and then you would multiply .15 and 8.40 to get 1.26!
Answer: 2 5/8 miles
Step-by-step explanation:
Because 6 1/8 - 3 1/2 = 2 5/8, Alice and Enrique will have 2 5/8 miles left to jog after their break.
Hope it helps :)
.5x=10+.25x
.25x=10
x=40
When you buy 40 songs
The cost equals 20$