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Ced
Posts:
1
From:
sydney
Registered:
10/22/10


Geometry  Proba  year 12  2 units  URGENT EXAM on Monday
Posted:
Oct 22, 2010 11:52 PM


Hi, I don't know if I should post my question here. This is for my son
here it is An enclosure is made of 3 enclosures, 1 big rectangle on and on the 2 small ones of the same measure
< y ><6y>
x PIG PEN
 Paddock for calves x PIG PEN  brick walllllllllllllllllllllllllllllllllll
Farmer Brown wishes to construct 3 rectangular enclosures. The paddock for the calves is to be 6 times as long and twice as wide as a pig pen. One pig pen and the calves' paddock have an existing brick wall as a boundary fence as shown. All other fences are to be constructed from 56 metres of wire mesch.
1. Let x metre be the width of a pig pen and y metres be its length. Show that y = 7  3/4x.
2. Hence show that the total area A square metres contained in the 3 enclosures is given by A= 14x(73/4x).
3. Show that A is a maximum when half the wire fencing has been placed parallel to the brick wall.  B. 1. A die whose faces numbered 1,2,3,4,5,6 is tossed twice. The sum S of the numbers which appear uppermost on the die is calculated. Find the probability that S is greater than 8.
2. It is known that a 4 appears on the die at least once in the 2 throws. Find the probability that S is greater than 8.
 Thank you very much



