# 5.2.1 Ratio, Rates and Proportions (I), PT3 Focus Practice

5.2.1 Ratio, Rates and Proportions (I), PT3 Focus Practice

Question 1:
Given x : y = 4 : 5 and x + y = 180. Find the value of x.

Solution:

Question 2:
Given x : y = 9 : 5 and xy = 16. Find the value of x + y.

Solution:

Question 3:
Amy, Rizal and Muthu donated to a charity fund in the ratio of 2 : 1 : 3. The total donation from Amy and Muthu was RM360.
Calculate the amount donated by Rizal.

Solution:
Amy : Rizal : Muthu = 2 : 1 : 3

Question 4:
In the figure, TU: UV : VW = 5 : 7 : 2.

If TU = 30 cm, what is the length of TW?

Solution:

Question 5:
In diagram below, ABC is a triangle.
The sides of the triangle are in the ratio AB : BC: CA = 4 : 7 : 6.
Find the difference in length, in cm, between AB and CA.

Solution:
$\begin{array}{l}AB:BC:CA=4:7:6\\ BC=35cm\\ \\ \frac{AB}{BC}=\frac{4}{7}\\ \frac{AB}{35}=\frac{4}{7}\\ AB=\frac{4}{7}×35\\ \text{}=20cm\\ \frac{CA}{35}=\frac{6}{7}\\ CA=\frac{6}{7}×35\\ \text{}=30cm\end{array}$

Difference in length between AB and CA
= 30 – 20
= 10 cm