Example 3

Contents

Example 3

In this page:

Worked Example 3

	Strategy 1
	Strategies 2 & 3

In this worked example, the strategies covered are:

(1) Make a Supposition

(2) Use an Equation

(3) Use Ratio

Worked Example 3

Mr. Lim had just bought a car and is deciding which type of petrol, Petrol X and Petrol Y, is cheaper. He found out the information of both types of petrol.

Petrol X --- 55 km/litres; Petrol Y --- 70 km/ litres

Furthermore, Petrol Y is 20% more expensive than Petrol Y. Thus, help Mr. Lim to find out which is more cost-effective.

Strategy 1: Make a Supposition

Suppose the price of Petrol X is $100. The price of Petrol Y = 120% x $100 = $120

Cost of amount of Petrol X needed to run 1 km = $/km = $/km = $/km

Cost of amount of Petrol Y needed to run 1 km = $/km = $/km = $/km

> Thus, Petrol Y is more cost-effective than Petrol X.

Now's your turn to try! Think of how to solve this problem using the other 2 strategies:

	Use an Equation
	Use Ratio

You can e-mail to me your solutions.

Let's proceed to Example 4.