Answer:
Answer:
\{ {{20x+30y=280} \atop {y=4x}} .{
y=4x
20x+30y=280
.
Where xx is the number of small boxes sent and yy is the number of large boxes sent.
Step-by-step explanation:
Let be xx the number of small boxes sent and yy the number of large boxes sent.
Since each small box can hold 20 books (20x20x ), each large box can hold 30 books (30y30y )and altogether can hold a total of 280 books, we can write the following equation to represent this:
20x+30y=28020x+30y=280
According to the information provided in the exercise, there were 4 times as many large boxes sent as small boxes. This can be represented with this equation:
y=4xy=4x
Therefore, the system of equation that be used to determine the number of small boxes sent and the number of large boxes sent, is:
\{ {{20x+30y=280} \atop {y=4x}} .{
y=4x
20x+30y=280
.
I'm going to use the substitution method.
If y = - 3/2 - 7, then:
1/2x + 5 = - 3/2x - 7
Combine like terms:
4/2x = - 12. Mutiply both sides by 2/4 to get x = -12 (2/4)
Simplify to get:
x = - 6.
Plug - 6 back in for x in either equation.
Y = 1/2( - 6) + 5 which becomes Y = - 3 + 5.
X = - 6, Y = 2
Divide 1/16 by 3/5 and you get .104 we can check by multiplying our answer by 3/5 and we get 1/16
Let x =lenght, y = width, and z =height
<span>The volume of the box is equal to V = xyz </span>
<span>Subject to the surface area </span>
<span>S = 2xy + 2xz + 2yz = 64 </span>
<span>= 2(xy + xz + yz) </span>
<span>= 2[xy + x(64/xy) + y(64/xy)] </span>
<span>S(x,y)= 2(xy + 64/y + 64/x) </span>
<span>Then </span>
<span>Mx(x, y) = y = 64/x^2 </span>
<span>My(x, y) = x = 64/y^2 </span>
<span>y^2 = 64/x </span>
<span>(64/x^2)^2 = 64 </span>
<span>4096/x^4 = 64/x </span>
<span>x^3 = 4096/64 </span>
<span>x^3 = 64 </span>
<span>x = 4 </span>
<span>y = 64/x^2 </span>
<span>y = 4 </span>
<span>z= 64/yx </span>
<span>z= 64/16 </span>
<span>z = 4 </span>
<span>Therefor the dimensions are cube 4.</span>
To find the contribution of each man (this is a sexist problem as women could work as well, but that’s besides the point) take 5/2 and then multiply that value by 20 and you’ll find it takes 50 hours for two men to do it.
Answer: 50 hours
