1.
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. (1 point)

y = 5z over x; five-thirds
t = 5x over z; 15
t = 6x over z; 18
t = 6z over x; 2

Question

1.  
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.  (1 point)

    y = 5z over x; five-thirds
    t = 5x over z; 15
    t = 6x over z; 18
    t = 6z over x; 2

anonymous · Answer

I would be so helpful if I was to know how to plug it in

anonymous · Answer

y=k x/z
  y = 18 when x = 15 and z = 5
pluuging these values we have 18=k(15)/5  or k=6
hence 
y=6x/z

now y =6(21)/7 =6*3=18

hence y= 6x over z; 18

anonymous · Answer

So it doesn't matter if it is a t= or a y= ?

anonymous · Answer

it should be y there might be a misprint or typo error...

anonymous · Answer

probably so...but thank you so much!!!! I really appreciate it( :