# If a box with a square cross section is to be sent by a delivery service, there are restrictions on its size such that its volume

If a box with a square cross section is to be sent by a delivery service, there are restrictions on its size such that its volume is given by V=x^2(81-3x) where x is the length of each side of the cross section in inches. A. Is V a function of x?
B. If V=V(x) , find V(14) and V(25)
C. What restrictions must be placed on x so that the problem makes physical sense

## This Post Has 4 Comments

1. daniel1480 says:

so she walks 3.5 mph, miles per hour, that's her walking speed rate.

so in 6 hours, she walked

3.5 miles

+ 3.5 miles

+ 3.5 miles

+ 3.5 miles

+ 3.5 miles

+ 3.5 miles

namely 6(3.5) miles in 6 hours.

she did that for 3 weeks, so she did it 3 times, 3 times that much is 6(3.5)+6(3.5)+6(3.5), or 3[ 6(3.5) ].

well, her regular speed is 3.5, so one-half her regular speed will be 3.5/2.

we know she walked one week for 4 hours at half her speed, that means she walked

3.5/2 miles

+ 3.5/2 miles

+ 3.5/2 miles

+ 3.5/2 miles

namely $\bf 4\left[\frac{3.5}{2} \right]$.

$\bf \stackrel{\textit{3 weeks at regular speed for 6 hours}}{3[~~6~(3.5)~~]}~~+~~\stackrel{\textit{one week for 4 hours at half-speed}}{1~~\left[ 4~\left(\frac{3.5}{2} \right) \right]}\\\\\\63~~+~~7\implies 70$

2. brandonm39 says:

so she walks 3.5 mph, miles per hour, that's her walking speed rate.

so in 6 hours, she walked

3.5 miles

+ 3.5 miles

+ 3.5 miles

+ 3.5 miles

+ 3.5 miles

+ 3.5 miles

namely 6(3.5) miles in 6 hours.

she did that for 3 weeks, so she did it 3 times, 3 times that much is 6(3.5)+6(3.5)+6(3.5), or 3[ 6(3.5) ].

well, her regular speed is 3.5, so one-half her regular speed will be 3.5/2.

we know she walked one week for 4 hours at half her speed, that means she walked

3.5/2 miles

+ 3.5/2 miles

+ 3.5/2 miles

+ 3.5/2 miles

namely $\bf 4\left[\frac{3.5}{2} \right]$.

$\bf \stackrel{\textit{3 weeks at regular speed for 6 hours}}{3[~~6~(3.5)~~]}~~+~~\stackrel{\textit{one week for 4 hours at half-speed}}{1~~\left[ 4~\left(\frac{3.5}{2} \right) \right]}\\\\\\63~~+~~7\implies 70$

3. timmonskids2681 says:

Step-by-step explanation:

you gotta find out what the number of the suplement is and then multiply that by two and then youll get your answer

4. carlos200411114 says:

The angle is 120 degrees.

Step-by-step explanation:

Supplementary angles add up to 180 degrees.

So if our angle is x it's supplement is 180 - x.

So we have the equation:

x = 2(180 - x)

x = 360 - 2x

3x = 360