Given:
Cost of two donuts and three cookies = $3.30
Cost of five donuts and two cookies = $4.95
To find:
The cost of each donut.
Solution:
Let x be the cost of each donut and y be the cost of each cookie.
Cost of two donuts and three cookies = $3.30
...(i)
Cost of five donuts and two cookies = $4.95
...(ii)
Multiply equation (i) by 2.
...(iii)
Multiply equation (ii) by 3.
...(iv)
Subtracting (iii) from (iv), we get
Divide both sides by 11.
Therefore, the cost of each donut is $0.75.
Answer:
x
=
−
20
1
2
Isolate the variable by dividing each side by factors that don't contain the variable.
Answer: (80% , 85%)
Step-by-step explanation:
We know that, confidence interval for population proportion is given by :-
(p-E , p+E)
, where p = sample proportion , E = Margin of error.
Given : Proportion of elementary school teachers who are female = 82%.
The article also states the maximum error of their estimate = 3%.
Then, the 90% confidence interval for the proportion of elementary school teachers who are female will be :
(82%-2% , 82%+3%)
= (80% , 85%)
Hence, the resulting 90% confidence interval for the proportion of elementary school teachers who are female = (80% , 85%)
Answer:
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Step-by-step explanation:
need more information in order to answer this.