Answer:
8 cylinders
Step-by-step explanation:
The surface area of a cylinder is given by the formula ...
A = 2πr(r +l) . . . . . for radius r and length l
__
The cylinders Rufus has each have an area of ...
A = 2π(5 cm)(5 cm +4 cm) = 90π cm² ≈ 282.74 cm²
That means 2500 cm² of paint will cover ...
2500 cm²/(282.74 cm²/cylinder) ≈ 8.84 cylinders
Rufus has enough paint to cover 8 cylinders completely.
I don’t know what the answer is I wish I could help
Answer: $70 per year.
Step-by-step explanation:
Let's say that x is the number of years that has passed and y is how much the stamp is worth.
So we know that in zero years the stamp was worth $420 because that is the time Sheri gave her brother Sam the stamp. That could bring up the coordinates (0,420) .
Now we know that in 8 years it was worth $980 and that could be the coordinates (8,980)
To find the rate of change we need to find the different between the y value and divide it by the difference in the x values.
420 - 980 = -560
0-8 = -8
-560/-8 = 70
The rate of change is 70 which means that it grew by $70 every year.
Answer:
the amount of time until 23 pounds of salt remain in the tank is 0.088 minutes.
Step-by-step explanation:
The variation of the concentration of salt can be expressed as:
being
C1: the concentration of salt in the inflow
Qi: the flow entering the tank
C2: the concentration leaving the tank (the same concentration that is in every part of the tank at that moment)
Qo: the flow going out of the tank.
With no salt in the inflow (C1=0), the equation can be reduced to
Rearranging the equation, it becomes
Integrating both sides
It is known that the concentration at t=0 is 30 pounds in 60 gallons, so C(0) is 0.5 pounds/gallon.
The final equation for the concentration of salt at any given time is
To answer how long it will be until there are 23 pounds of salt in the tank, we can use the last equation:
The answer is C because 3/4 is the biggest of them all and the only one saying that is C.
