Answer: 58.666666666667
Step-by-step explanation:
my brain
Answer: b. Lin buys a pack of 87 pencils. She gives 39 to her teacher and shared the remaining pencils between herself and 3 friends.
Step-by-step explanation:
Lin buys 87 pencils which is why the entire number line adds up to 87.
She gave 39 of these pencils to her teacher which s why there is a section of the number line that is unlike the rest and is 39 in number.
The rest of the number line is a set of 4 spaces which are equal.
Lin shared the remaining pencils between herself and 3 friends which means she shared the pencils with 4 people. These four equal quantities of pencils are the 4 spaces.
2x=16-2y
x=8-y
6(8-y)+4y=38
48-6y+4y=38
48-2y=38
-2y=-10
y=5
8-5=x
x=3 <-Answer
Answer:
x = 10 cm, y = 5 cm gives a minimum area of 300 cm^2.
Step-by-step explanation:
V= x^2y = 500
Surface area A = x^2 + 4xy.
From the first equation y = 500/x^2
So substituting for y in the equation for the surface area:
A = x^2 + 4x * 500/x^2
A = x^2 + 2000/x
Finding the derivative:
dA/dx = 2x - 2000x^-2
dA/dx = 2x - 2000/x^2
This = 0 for a minimum/maximum value of A, so
2x - 2000/x^2 = 0
2x^3 - 2000 = 0
x^3 = 2000/ 2 = 1000
x = 10
Second derivative is 2 + 4000/x^3
when x = 10 this is positive so x = 10 gives a minimum value of A.
So y = 500/x^2
= 500/100
= 5.