Answer:
He received 10 dimes and 15 quarters.
Step-by-step explanation:
Dimes = $0.10
Quarters = $0.25
Variable x = dimes
Variable y = quarters
Create a pair of linear equations:
0.10x + 0.25y = 4.75
x + y = 25
Isolate any variable, using an equation of your choice:
x + y = 25
x = 25 - y
Plug in this new value of x into the other equation:
0.10(25 - y) + 0.25y = 4.75
Use the distributive property:
2.5 - 0.10y + 0.25y = 4.75
Combine like terms:
2.5 + 0.15y = 4.75
Isolate variable y:
0.15y = 2.25
y = 15
Plug in the value of y into any equation:
x + y = 25
x + 15 = 25
Isolate variable x:
x = 10
Answer:
The volume increases at a rate of 
Step-by-step explanation:
The rate of change of the radius with respect to time is 4 mm / s.
So:

Now we must find a relationship between the volume of a sphere and its radius.
The equation of the volume of a sphere is:

So:

The diameter of the sphere is 100 mm. Therefore its radius is 100/2 = 50 mm.
So:

The volume increases at a rate of :
40000 π mm ^ 3 / s = 125663.71 mm^3/s
Answer:
28 miles
Step-by-step explanation:
308/11 = 28 miles per gallon of gas