3


The sum of the ratio parts: 9 + 5 + 3 = 17 27 cm = 9


So 1 4.1


___ 17 = 27 ÷ 9 = 3


___ 17


Breadth = 5 × 3 = 15 cm Height = 3 × 3 = 9 cm


Capital investment of Andiswa : Benjani : Chris = 25 000 : 50 000 : 40 000 = 5 : 10 : 8


4.2 The sum of the ratio parts = 23 R9 200 ÷ 23 = R400 Andiswa will get 5 × 400 = R2 000 Benjani will get 10 × 400 = R4 000 Chris will get 8 × 400 = R3 200


5.1


Cost during peak hours = 2,25 × 3 = R6,75 Cost during off-peak hours = 1,18 × 3 = R3,54 Difference = R6,75 − R3,54 = R3,21


5.2 45 seconds = 0,75 minutes Cost during peak hours = 2,65 × 0,75 = R1,9875 Cost during off-peak hours 1,30 × 0,75 = R0,975 Difference = R1,9875 − R0,975 = R1,0125 = R1,01 to two decimal places


Remedial


• Some learners may have difficulty expressing a ratio as a percentage. Help them with easy examples (such as 2 : 5 = 4 : 10 = 40 : 100 = 40%) at first, followed by more challenging ones.


• Some learners may have difficulty simplifying ratios. Help them with easy examples (such as R120 : R80 = 12 : 8 (by dividing by R10) = 3 : 2 (by dividing by 4) at first, followed by more challenging ones.


Exercise 2 Guidelines on how to implement this activity


Revise the concepts speed, distance and time including the various units commonly used for this. Demonstrate by means of Worked examples on the board. Let the learners start Exercise 3 in the class and finish it, if necessary, for homework.


Suggested answers 1.1


S = D


__ T


= 1 500 = 83, ˙


_____ 18


3 km/h 1.2 T = D


__ S


= 1 500 = 20,8 ˙


_____ 72


3 hours = 20 hours + (0,8 ˙ 3 × 60 minutes) = 20 hours 50 minutes Chapter 1: Numbers and integers 39 Learner’s Book page 30


CHAPTER 1


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