ECZ 2015 · O-Level Paper 2 · Question 12 — Linear Programming
Question from ECZ 2015 · O-Level Paper 2 · Question 12
(a) The graph below shows three inequalities that satisfy region R.
(a(i)) Write the three inequalities that define the unshaded region R.[6]
Verified working — step 1
The line through the origin and (5, 5) is y = x; R lies below it, so y ≤ x.(a(ii)) Find the largest value of 4x - 5y within region R.[1]
Verified working — step 1
Evaluate 4x - 5y at each vertex of R.(b) Before the ZESCO prepaid meters were installed in Mr Malaiti's house, his electricity bill used to consist of a fixed charge of K20.00 and 20 ngwee for every unit of electricity used.
(b(i)) Given that in a particular month, he used 387.3 units, calculate the amount he paid to ZESCO.[2]
Verified working — step 1
Bill = fixed charge + per-unit charge.(b(ii)) In another month, he was given a bill of K120.40. Find the number of units he used in this month.[3]
Verified working — step 1
Remove the fixed charge first.The full step-by-step working and final answer are included with Premium — checked against ECZ marking standards.
Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.
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