Further Mathematics Paper 2, Nov/Dec. 2012
 Questions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Main
Weakness/Remedies
Strength
Question 4

Indicate by shading graphically, the set of all points p(x,y) in the OXY plane that satisfy simultaneously the inequalities:
2x – y ≥  - 4;
x + y ≤  10;
y – x > 0;
y 2 and
x ≥ 0.

(b)        Using the graph, find the values of x and y for which 10x + 5y is maximum.

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Observation

IThis question was reportedly poorly attempted by majority of the candidates.  Teachers as well as  candidates were encouraged to put in more effort at the teaching and learning of this topic while preparing for the examinations.  Candidates were expected to draw the graph of the inequalities on the same graph sheet and using the same scale and axes as shown.

The vertices of the shaded area would now be checked with the expression 10x + 5y to obtain the vertex p(x,y) and hence, the value of x and y for which the expression was maximum.  These values were x = 5 and y = 5.