Step-by-step explanation:
the change in cost of 145-135.50 = 9.50 for an increase of students from 25 to 30. The ratio of change of cost to change of students = 9.50/5 = 1.9 and becomes the slope coefficient "m" in the formula y= mx + b. y = the total cost, mx becomes the variable cost and b becomes the fixed cost. To find b, use the data point given where the total cost = $135.50 when the students = 25, or 135.50 = 1.9*25 +b. Solving for b yields $ 88. Note that the other data point is where the total cost is $145 for students = 30. Using the new total cost equation shows that 30*1.9+88= 145
Circumference of the circle is given as = 220 feet
We have to find the diameter.
Circumference is found as = 2 * PI * r
r=35.03
Diameter is 2*radius
Diameter = 
= 70.06
Hence, diameter of the circle is 70.06 feet.
Cost of 1 plant = $ p
Cost of 4 plants = $(4p)
Cost of a 10-gallon tank = $10
Cost of a water dish = $3
Total cost = 4p + 10 + 3 = 4p + 13
Answer:
15 students (30% of the students in class) scores a 95 on a quiz.
Therefore the total number of students (100% of the students) in class is:
N = 15 x 100/30 = 50 (students)
(This calculation is inferred from a ratio that 15/N = 30/100).
Denote the number of students who scored a 95 on a quiz is a, the total number of students in class is b.
Then the equation that related a and b is:
b = (100/30) x a
Hope this helps!
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