Question

IF Z VARIES DIRECTLY AS X ND INVERSELY AS Y .FIND THE PERCENTAGE INCREASE IN Z TO AN INCREASE OF 12% IN X AND 20% IN Y.

Answer 1

z is directly proportional to X
z is inversely proportional to y
z is directly proportional to X/y
z=xk/y
k =zy/X

let the values of X one , Y one , Z one =100
then the value of X two is 112(since it is increased by 12%)
Y two is 80 (since it is decreased by 20%)
Z two =?

by the formula,
Zone * Y one / X one =Z two * Y two /X two
100*100/100=Z two *80/112
100*112/80=Z two
1120/8=Z two
Z two =140

therefore the z is increased by 40%.....




hope it helps u buddy...