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 %
<gadget id="calculator">100 + 40</gadget>
<output>140</output>

<gadget id="calculator">100 / 140</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">1 - (5/7)</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(2/7) * 100</gadget>
<output>200/7 = around 28.571429</output>

<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?
multiply(subtract(const_1, divide(const_100, add(const_100, 40))), const_100)
x * y = constt . let x = y = 100 in beginning i . e . x * y = 100 * 100 = 10000 x ( 100 ) - - - becomes - - - > 1.4 x ( 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 % c