Question

Find the constant of variation if y varies inversely as x, and y = 15 when x = 5.

Assume that y varies inversely as x. Find x when y= 6 if y = 4.2 when x = 10.

Answer 1

Help! :O

Answer 2

"y varies inversely as x"

So it's y = k/x where k is an unknown constant. You need to find k.

Answer 3

Let's do the first one.\[y = \dfrac{k}{x}\Rightarrow 15 = \dfrac{k}{5}\]

Answer 4

Can you find the value of k?

Answer 5

hmm

Answer 6

How do I find it

Answer 7

3?

Answer 8

All you have to do is to isolate k. So we have to do something with 5 in denominator.

Answer 9

Ohh

Answer 10

15 * 5? or 15/5

Answer 11

15*5

Answer 12

because you can remove 5 in denominator by multiplying both sides by 5.

Answer 13

75

Answer 14

??
@geerky42

Answer 15

Yes.

Answer 16

So the answer for that one is 75

Answer 17

Yes. 75 is the constant of variation.

Answer 18

Now this one 'Assume that y varies inversely as x. Find x when y= 6 if y = 4.2 when x = 10.

Answer 19

This time, it take a little more work. First you need to find k again. Can you do it this time by yourself?

Answer 20

I will try

Answer 21

When x=5, y=15 so x/y=1/3 so if y=5 then x/5=1/3 so x=5/3.

Answer 22

hmmmm