<PRE><B>Question 141445</B>
A lawn mower of width 1m is used to mow a rectangular lawn of dimension 60mx40m. The mowing is done starting from the corner towards the center. How many times should the mower be moved along the garden for 3/4th of garden to be mowed?
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Assume you mean 3/4 of the lawn, not the garden. (Big trouble if you mowed the garden around here.)
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Find the area of 3/4 of the lawn
60 * 40 * 3/4 = 1800 sq/m 
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Let x = no. of rounds made on the lawn to complete 3/4 of it
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Each round subtracts two meters from both dimensions, so we have:
(60-2x)*(40-2x) = 1800
FOIL
2400 - 120x - 80x + 4x^2 = 1800
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2400 - 200x + 4x^2 - 1800 = 0
Arrange as a quadratic equation
4x^2 - 200x + 600 = 0
simplify, divide by 4
x^2 - 50x + 150 = 0
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Use the quadratic formula to find x: a=1; b=-50; c=150
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The reasonable answer I got was approx 3.2 rounds</PRE>