<PRE><B>Question 934672</B>
y = k/x is the equation for inverse proportion.


let y1 = k/x


let y2 = k/(.8x)


ratio of y2 to y1 = y2 / y1 = (k/.8x) / (k/x) = (k/.8x) * (x/k) = 1/.8 = 1.25


if x decreases 20%, then y increases 1/20% which is equal to 1.25 times.


example:


y = 200 when x = 100


y = k/x gets you k = 20,000.


x decreases by 10% makes x = 80.


y = 20,000 / 80 becomes y = 250.


250 / 200 = 1.25


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