Find the approximate area of a circle with radius equal to 8 feet
2 answers:
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Answer:
C = $2.40
n = 6
Step-by-step explanation:
For Noelle,
Equation that represents the monthly cost 'C',
C = 0.2n + 1.20
Here, n = number of checks written in a month
For Micah,
Monthly cost for writing checks 'C' = $1.20
Number of checks 'n' = 3
Since, Cost of writing checks ∝ Number of checks written
C' ∝ n
C' = kn
k =
Here, k = proportionality constant
For C' = 1.2 and n = 3
k =
k = 0.4
Equation will be,
C' = 0.4n
For any month C = C'
Therefore, 0.2n + 1.20 = 0.4n
0.4n - 0.2n = 1.20
0.2n = 1.20
n = 6
Number of checks written by Noelle and Micah = 6
For n = 6,
C = 0.2(6) + 1.20
C = $2.40
Cost of writing checks = $2.40
Answer:
30 gallons of 20% acid solution should be mixed.
Step-by-step explanation:
Let x gallons of a 20% acid solution was mixed with 30 gallons of a 40% solution, to obtain a mixture of 30% acid solution.
Therefore, final volume of the solution will be (x + 30) gallons.
Now concept to solve this question is
20%.(x) + 40%.(30) = 30%.(x + 30)
0.20(x) + 0.40(30) = 0.30(x + 30)
0.20x + 12 = 0.30x + 9
0.30x - 0.20x = 12 - 9
.10x = 3
x =
x = 30 gallons
Therefore, 30 gallons of the 20% acid solution should be mixed.