SPM Mathematics Trial 2021 (Selangor), Paper 2 (Question 5 & 6)

Question 5:
Diagram 3 shows a shaded region which satisfies three inequalities.
State all the inequalities.


Solution:

$\begin{array}{l}\text{Shaded region above the solid line},y=\frac{3}{2}\text{ is }y\ge \frac{3}{2}.\\ \\ \text{At y-intercept},c=6.x-intercept\; =6\\ \text{gradient, }m=-\frac{6}{6}=-1\\ y=mx+c\\ y=-x+6\\ \therefore \text{Shaded region below the solid line is }y\le -x+6.\\ \\ \text{At origin, y-intercept}c=0,\\ \text{gradient, }m=\frac{1.5-0}{0.5-0}=3\\ y=mx+c\\ y=3x+0\\ y=3x\\ \therefore \text{Shaded region below the dashed line is y}<3x.\end{array}$

Question 6:
Mr. Chew Eng is a mechanic. His monthly basic salary is RM 1 400. He received monthly overtime allowance of RM450 per month. He lives in a terrace house with the rental rate of RM550 per month. Utility bill, monthly car installment and the cost of his petrol are RM350, RM390 and RM180 respectively. Every month, he spends RM750 for his food.
Calculate and state Mr. Chew Eng cash flow. Hence, give a suggestion on how he can improvise his cash flow.
[4 marks]


Solution:
Total income = RM1 400 + RM450 = RM1 850
Total expenses = RM550 + RM350 + RM390 + RM180 + RM750 = RM2 220

Cash flow = Total income – Total expenses
= RM1 850 – RM 2 220
= –RM370 (Negative cash flow)

Mr. Chew Eng has a negative cash flow because his total expenses > total income.

Suggestions to Mr. Chew Eng:
– Reduce food spending by practising home cooking.
– Reduce petrol cost by using public transport.
– Reduce utility bill by reducing the electricity and water consumption.
(any one of the suggestion)