Answer:
Both of them are correct.
The perimeter is found by adding up all four sides. If you notice, one of them is width and one of them is length. A rectangle has four sides, two width and two length.
l= length and w=width so P=2l+2w.
But, we can combine them by factorizing 2l+2w.
Lets see what we can pull out. We can only pull out 2.
2(l+w)=2l+2w.
2(l+w)=P
Both of them are correct.
Hope this helps plz hit the crown :D
Answer:
8b- 13 6/7
Step-by-step explanation:
A product of 8 and b just means 8 x b or 8b.
13 6/7 less than that product means subtraction.
Therefore, it would be 8b - ![13\frac{6}{7}](https://tex.z-dn.net/?f=13%5Cfrac%7B6%7D%7B7%7D)
Answer:
a) the radius of the balloon increases at a rate of 5.42 in/s
b) the surface area of the balloon increases at a rate of 3 in²/s
Step-by-step explanation:
a) since the volume of a sphere V is
V= 4/3*π*R³
where R= radius , then the rate of change of the volume is
V' = dV/dR= 4*π*R²
using the chain rule
dV/dt = dV/dR*dR/dt
thus
k = 4*π*R² * dR/dt
dR/dt = k/(4*π*R²)
replacing values
dR/dt = k/(4*π*R²) = (33 in³/s) /(4*π*(22 in)²] = 5.42 in/s
then the radius of the balloon increases at a rate of 5.42 in/s
b) since the surface area is
S=4*π*R²
then
S' = dS/dR= 8*π*R
and
dS/dt = dS/dR*dR/dt = 8*π*R * k/(4*π*R²) = 2*k/R
replacing values
dS/dt = 2*k/R = 2*(33 in³/s)/( 22 in) = 3 in²/s
then the surface area of the balloon increases at a rate of 3 in²/s
Every 5 red cars there are 3 Blue cars,
So if there are 40 red cars,
there are going to be 24 Blue cars
40 divided by 5 which is 8
Multiply 3 × 8 which is ( 24 blue cars )