Question

Suppose c and d vary inversely, and d=2 when c=17.

a)write an equation that models the variation

b)find d when c=68

Answer 1

The inverse variation equation is this one:
\[c=\frac{ k }{ d }\],
where k is the constant of variation. Solve it like this, first for k

Answer 2

so for a it is: 17=k/2

Answer 3

\[c=\frac{ k }{ d }\]
fill in the values they gave you:
\[17=\frac{ k }{ 2 }\]
and solve for k first.

Answer 4

k= ???

Answer 5

k = 34

Answer 6

Yes! Now use that k value to solve for d when c = 68. Any ideas on how to set it up?

Answer 7

The same equation is used, but now you have a k value and a c value to use to help find d.

Answer 8

sorry my brain just died lol

i couldnt think of anything for a minute

Answer 9

It's ok! This is kinda daunting, I get it!

Answer 10

68=34/d?

Answer 11

so d = 2

Answer 12

\[c = \frac{ k }{ d }\]
and we have k to be 34 and c to be 68
\[68=\frac{ 34 }{ d }\]
and 68d = 34

Answer 13

No, d doesn't equal 2...watch:

Answer 14

oh its 1/2

Answer 15

\[d=\frac{ 34 }{ 68 }\]
\[d=\frac{ 1 }{ 2 }\]

Answer 16

Good! See how that works?! Good job!!

Answer 17

so....

a) 68=34/d

Answer 18

b) d = 1/2

Answer 19

yes, that's correct

Answer 20

ok thx

Answer 21

Any time!