Question

I need help please..

x varies inversely as v, and x=48 when v=8. Find x when v is 64.

A. x=6
B. x=64
C. x=8
D. x=48

Answer 1

inversely think divides
x=k/v
where k is the constant of variation

Answer 2

use (x,v)=(48,8) to find the constant k

Answer 3

then once we obtain k
we will go back to x=k/v
where we know k now
and then replace v with 64 and find x

Answer 4

v = k/x

8 = k/48

8*48 = k

Answer 5

k = 384

Answer 6

Now,

v = k/x

Taking v as 64 and k as 384

v = k/x

64 = 384/x

64x = 384

x = 384/64

Answer 7

Okay. I see what you are saying.

Answer 8

64 times 6 is equal to 384

Answer 9

Therefore, x would 6.

Answer 10

Getting it?

Answer 11

Thank you. I understood well! It made more sense. Now, would this still imply to x varies inversely as y^2, & x=4 when y=10. Find x when y=2.

Answer 12

x = y^2/k

Answer 13

2 = 10^2/k

Answer 14

2 = 100/k

2k = 100

k = 100/2

k = 50

Answer 15

It would be 50

Answer 16

I think I made a mistake.

Answer 17

I am understanding better. But my answer choices are a. X=16 b. X=5 c. X=80 d. X=100

Answer 18

What are your options?

Answer 19

Those are my options.

Answer 20

Wait!

Its

x = k/y^2

Answer 21

x is 4 and y is 10

Answer 22

4 = k/10^2

4 = k/100

4*100 = k

400 = k

Answer 23

Now, we have to find x but y is given as 2..

Can you find x ??

k = 400 and y = 2

Answer 24

So, do I divide?

Answer 25

x = k/y^2

Answer 26

k is 400 and y is 2

Answer 27

So, my answer is d?

Answer 28

Yes absolutely right...

Good Job..

Answer 29

Thank you!!!!

Answer 30

I think I did this one right. But I got a little confused.

~ You have 332 of fencing to enclose a rectangular region. What is the maximum area?

I got a the first time and b the second time.

Answer 31

A. 6889 square feet
B. 6885 square feet
C. 110,224 square feet
D. 27,556 square feet

Answer 32

2L + 2W = 332
and L x W = y
so from eqn 1, L = 332/2 + W
so (332/2 + W) x W = y
166W + W^2 = y
when derivative of y = 0 = maximum area
y' = 2W + 166
0 = 2W +166
-166 = 2W
W = 83

therefore as 2L +2W =332 and w = 83, L must =83 also
so L x W =A
83 x 83 = 6889

A

Answer 33

So, it is A and I was right the first time?

Answer 34

Yes...!

Answer 35

Thank you! I am understanding much much better.

Answer 36

:)