Page 10 - Mathematics_Form_Two

Rates and variations

16. Study the following figure which shows different altitudes (in thousands feet)
attained by a plane and then answer the questions that follow.

7 D
C E
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FOR ONLINE READING ONLY
A A B F G
Mathematics for Secondary Schools 3 2 1
5
4
Feet

1
0
2
7
6
9
8
4
3
5
Minutes 10 11 12 13 14 15 16 17 18 H 19
(a) During the first 5 minutes of flight, the plane took off to the altitude shown
by point A. Estimate the rate of change in altitude.
(b) Between points E and F, the plane is descending. Estimate the rate of
change of altitude during this time.
(c) Is the rate of change in (b) positive or negative? Give reasons for your
answer.

(d) Find the rate of change in altitude between points C and D. Is this rate
greater or less than the rate between points D and E? How does the graph
visually show that the two rates are different?
(e) Can the rate of change between any two points be 0? Briefly explain and
give an example from the figure.

17. Ana and Lina can weed a garden in 2 hours. Working alone, Ana can do the same
work in 3 hours. How long would Lina weed the garden alone?

Exchange rates
In any country, peopleexpect to do transactions in in the currency of of their own country.
When money from country A is to be used in country , it is necessary to exchange the
currency of country A to the currency of country B. Various currencies in the world are
linked together by exchange rates. This enable smooth transfer of money and payments
to take place between countries.

Engage in Activity 1.2 to explore more about the concept of currency exchange in real-
life situations.

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Student's Book Form Two

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MATHEMATIC F2 v5.indd 4
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