Answer:
(1/4) hr/mile
Step-by-step explanation:
4 mph can be rewritten using other units of measurement:
Suppose we convert 'miles' to 'feet:'
Then:
4 miles 5280 ft
---------- * ------------- = 21120 ft/hr
1 hr 1 mile
Note that we could invert 4 mph and obtain
1 hr
-------- or (1/4) hr/mile
4 mi
We know that Step 1 is correct, because it is just a restatement of the equation. Therefore, we can eliminate Step 1:
2(5y – 2) = 12 + 6y
In Step 2, the student tried using the Distributive Property. The Distributive Property can be written as one of the two following formulas:
a(b + c) = ab + ac
a(b – c) = ab – ac
In this case, we'll use the second formula. Substitute any known values into the equation above and simplify:
2(5y – 2) = 2(5y) – 2(2)
2(5y – 2) = 10y – 4
In Step 2, the student calculated 2(5y – 2) to equal 7y – 4. However, we have just proven that 2(5y – 2) is equal to 10y – 4.
The student first made an error in Step 2, and the correct step is:
Step 2: 10y – 4 = 12 + 6y
I hope this helps!
Answer:
The water level is dropping at a rate of 0.24 ft/s
Step-by-step explanation:
Here, we simply want to calculate the change in depth (height of the cone) , given the volume change
Mathematically, we have the volume of a cone as;
V = 1/3 * π * r^2 * h
we are given dv/dt as 12 ft^3/m
dv/dh = 1/3 * π * r^2
Substituting the value for the radius, we have
dv/dh = 1/3 * 22/7 * 4^2 = 50.29
dh/dt = dh/dv * dv/dt
dh/dv = 1/(dv/dh) = 1/50.29
Thus,
dh/dt = 1/50.29 * 12
dh/dt = 0.24 ft/s
Answer:B
Step-by-step explanation:
Answer:
Length = 11.25 and width = 3.75 inches.
Step-by-step explanation:
You must mean that the length is 3 times its width.
If the the width is x then the length is 3x inches.
Perimeter = 2*length + 2*width.
2(3x) + 2x = 30
6x + 2x = 30
8x = 30
x = 3.75.
3x = 11.25.
