Page 8 - Mathematics_Form_Two

Rates and variations

150 km Rate of growth of seedling B
Thus, speed = 8 cm
3hrs = _
= 0 . 67 cm per day
12 days
50 km= per hour
Therefore, the rate of travel of the car is The growth rate of seedling B is higher
50 km in every hour. than that of seedling A.
FOR ONLINE READING ONLY
Therefore, seedling B was growing
Mathematics for Secondary Schools If a water tank fills up with 200 litres of Example 1�4
Example 1�2
more quickly than seedling A.

water in 5 minutes, what is the rate of
flow of water?
Two pipes, A and B are used to fill a
water tank. Pipe A can fill the tank in
Solution
Given the volume of water is 200 L and
tank in 4 hours. If both pipes are opened
the time the tank takes to be filled is 6 hours, while pipe B can fill the same
at the same time, how long will it take to
5minutes. fill the tank?
Volume
Rate of flow =
Time Solution
200 L Pipe A fills the tank in 6 hours, so it fills
=
5min 1 of the tank in 1 hour.
40L/min= 6

Therefore, water enters the tank at the Pipe B fills the tank in 4 hours, so it fills
rate of 40 litres per minute. 1 of the tank in 1 hour.
4

Combined rate = Rate of A + Rate of B
Example 1�3
1
A student had two plant seedlings. She Combined rate = + 1
measured the rate at which the seedlings 6 4
were growing. Seedling A grew 5 cm in Combined rate = 23+ = 5
10 days and seedling B grew 8 cm in 12 12 12
days. Which seedling was growing more Therefore, both pipes together fill 5
quickly? of the tank in 1 hour. 12

Solution If 5 of the tank is filled in 1 hour, then
The rates of growth of the two seedlings 12
is computed as follows: the time taken to whole tank 12 will be;
Rate of growth of seedling A Time = Whole tank 12
5 cm
= 0 . 5 cm per day
= _ Combined rate
10 days

2
Student's Book Form Two

11/10/2024 20:11:06
MATHEMATIC F2 v5.indd 2
MATHEMATIC F2 v5.indd 2 11/10/2024 20:11:06