The product of x and y is a constant. If the value of x is increased by 40%, by what percentage must the value of y be decreased?	Select
A) 34%  B) 36%  C) 28.57%  D) 30%  E) 32%
x*y = constt.   Let x = y = 100 in beginning   i.e. x*y = 100*100= 
<gadget id="calculator">100*100</gadget>
<output>10_000</output>
10000   x (100) ---becomes---&gt; 1.4x (140)   i.e. 140*New 'y'= 10000   i.e. New 'y' = 10000/140 = 71.43   i.e. y decreases from 100 to 71.43 i.e. Decrease of 28.57%   28.57%
<result>C</result>
The product of x and y is a constant. If the value of x is increased by 40%, by what percentage must the value of y be decreased?