SPM 2017 Add Maths Paper 2, Question 14Linear Programming

Solved on video in English and Bahasa Melayu · 10 marks · Form 5, Linear Programming · 6:30 video

The question

Use a graph paper to answer this question. An entrepreneur wants to produce two types of toys, P and Q by using a machine. In a day, the machine produces x number of type P toys and y number of type Q toys. The time required to produce a type P toy is 6 minutes and the time required to produce a type Q toy is 5 minutes. The production of the toys is based on the following constraints: I: The total number of toys produced must be more than 40 units in a day. II: The machine can operate for only 15 hours a day. III: The ratio of the number of type P toys to the number of type Q toys is at most 3:5. (a) Write three inequalities, other than x ≥ 0 and y ≥ 0, that satisfy all the above constraints. (b) Using a scale of 2 cm to 20 toys on both axes, construct and shade the region R which satisfies all the above constraints. (c) Using the graph constructed in 14(b), find the range of total sales that can be obtained if the selling price of a type P toy is RM5 and the selling price of a type Q toy is RM3.

[10 marks]

SPM 2017 Add Maths Paper 2, Question 14: the question as drawn in Eduly's video6:30

Step 1

Constraint I: total toys more than 40 a day: x + y > 40

Why this step

'More than 40' means strictly greater, so we use > not ≥. Points on x + y = 40 are not allowed, so that line is dashed.

7 more steps, each with the reason for it, in the full solution

Final answer

(a) x + y > 40; 6x + 5y ≤ 900; 3y ≥ 5x. (b) Region R shaded (see video). (c) RM120 < P ≤ RM625

Where students lose marks

Watch out: 'more than 40' is strict, so use > (dashed line). Test every corner of R to find both minimum and maximum sales.

Watch every step of this question solved on video (6:30), with the reason behind each step and a box that checks your own answer.

No card. Every past-year question on video, in English and BM.

More Linear Programming questions

Questions are re-typeset by Eduly for study and commentary. Eduly is not affiliated with Lembaga Peperiksaan Malaysia or the Ministry of Education.