SOLUTION: X varies directly with y and inversely with z. If y is quadrupled and z is quadrupled, how does x change? My work: I'm pretty sure that x is then quadrupled, also. Am I right

Algebra ->  Expressions-with-variables -> SOLUTION: X varies directly with y and inversely with z. If y is quadrupled and z is quadrupled, how does x change? My work: I'm pretty sure that x is then quadrupled, also. Am I right      Log On


   

Question 355246: X varies directly with y and inversely with z. If y is quadrupled and z is quadrupled, how does x change?
My work:
I'm pretty sure that x is then quadrupled, also. Am I right?
I'd appreciate help! Thanks! :)
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
"X varies directly with y and inversely with z" means that x=%28ky%29%2Fz

Now "If y is quadrupled and z is quadrupled", then x=%28k%284y%29%29%2F%284z%29 (ie multiply y and z by 4)


However, notice that the 4's will divide and cancel out. This will leave you with the original equation. So quadrupling both y and z does not change 'x'


Ex: Say that x=1%2F2 (ie k=1, y=1, z=2). Quadruple 1 and 2 to get x=%281%2A4%29%2F%282%2A4%29=4%2F8. So x=4%2F8, but 4%2F8=1%2F2, which means that x=1%2F2