Question

suppose that y varies directly with x and inversely with z, and y=18 when x=15 and z=5. write the equation that models the relationship. then find y when x=21 and z=7.
a. y=5z/x ; 5/3
b. t=5x/z ; 15
c. t=6x/z ; 18
d. t=6z/x ; 2

Answer 1

Then \[y ~~~\alpha~~~~\frac{x}{z}\]
So \[y= k*\frac{x}{z}\] [Where \(k\) is a constant of proportionality]

Put the values of y,x,z and get the value of k.
Then use the value of k for the question.

Got it? :)

Answer 2

i got B.

Answer 3

Are you sure? What method did you use? :D

Answer 4

isnt c the answer?

Answer 5

@AkashdeepDeb @historylover

Answer 6

It is. But the answer is not important. Understanding it, is.

Answer 7

yeah she needs an explanation

Answer 8

i just re-worked it. i had an error in my scratch work the first time

Answer 9

Ok. The answer is 'c' now. You understood why?

Answer 10

yep!