14. Audrey and Belle have some money each. If Audrey spends $18 and Belle spends $24 each day, Audrey will still have $25 left when Belle has spent all her money. If Audrey spends $13 and Belle spends $30 each day, Audrey will still have $139 left when Belle has spent all her money. How much money do they have altogether? [4 marks]
18 : 24 = 3 : 4 = 45 : 60
13 : 30 = 26 : 60
45 – 26 = 19
19 u -- > 139 – 25 = 114
1 u -- > 114 ÷ 19 = 6
105 u -- > 105 x 6 = 630
630 + 25 = $655
They have $655 altogether.
15. The series of figures below are made of cubes. Study the diagram below and answer the following questions.
a) How many cubes are there in Figure 6? [2]
b) Which figure will have 120 cubes? [2]
1
1 + 3 = 4 1 + 2 = 3
1 + 3 + 6 = 10 1 + 2 + 3 = 6
1 + 3 + 6 + 10 = 20 1 + 2 + 3 + 4 = 10
1 + 3 + 6 + 10 + 15 = 35 1 + 2 + 3 + 4 + 5 = 15
1 + 3 + 6 + 10 + 15 + 21 = 56 1 + 2 + 3 + 4 + 5 + 6 = 21
a) There are 56 cubes in Figure 6.
56 + 28 = 84 21 + 7 = 28
84 + 36 = 120 --> Figure 8 28 + 8 = 36
b) Figure 8 will have 120 cubes.
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