RGS Primary 2009 PSLE Math Prelim Paper 2 Q14

John shifted the decimal point of a number twice to the left to obtain a new number. The difference between the new number and the original number was 136.62.

a) How many times the new number is the original number?

b) What is the sum of the 2 numbers?

Solution

a)

Answer: 100 times

b)

Original number --> 1 unit

New number --> 100 units

100 units - 1 unit --> 136.62
99 units --> 136.62

1 unit --> 136.62 divided by 99 = 1.38

Sum of the two numbers

--> 100 units + 1 unit = 101 units

101 units --> 101 x 1.38 = 139.38

Answer: 139.38

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ACS Primary 2009 PSLE Math Prelim Paper 2 Q4

Barry poured 230 ml of lemonade into a jug that already contained 1.6 litres of juice. He then poured out the drink equally into 3 cups. What is the volume of the drink in each cup?

Solution

0.23 + 1.6 = 1.83

1.83 divided by 3 = 0.61

Answer: 0.61 litre

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Nanyang Pri Sch 2009 P6 CA1 Math Paper 2 Q14

Mr Lim paid $134.40 for some jackfruits and pomeloes. The cost of the pomelo was 0.8 that of a jackfruit. A pomelo cost $5.60. If all the pomeloes cost $22.40 more than the jackfruits, how many fruits did he buy?

Solution

2 units --> $134.40 - $22.40 = $112
1 unit --> $112 divided by 2 = $56

Cost of Pomeloes
--> $56 + $22.40 = $78.40

Number of Pomeloes bought
--> $78.40 divided $5.60 (per pomelo)
= 14 pomeloes

Cost of of 1 pomelo is 0.8 of 1 jackfruit
Pomelo --> 8 units
Jackfruit--> 10 units

(Pomelo) 8 units --> $5.60
1 unit --> $5.60 divided by 8 = $0.70
(Jackfruit) 10 units --> 10 x $0.70 = $7

Number of Jackfruits bought
--> Total cost - cost of pomeloes
$134.40 - $78.40 = $56
$56 divided by $7 (per jackfruit) = 8 (jackfruits)

Total number of fruits
14 (pomeloes) + 8 (jackfruits) = 22 fruits

Answer: 22 fruits

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Nanyang Pri Sch 2009 P6 CA1 Math Paper 2 Q5

A container with Bottle A placed in it has a mass of 4.27 kg. An identical container with Bottle B placed in it has a mass of 6.58 kg. The mass of Bottle A is 1/3 that of Bottle B. What is the mass of the Bottle A? Give your answer correct to 2 decimal places.

Solution

Bottle A --> 1 unit
Bottle B --> 3 unit

Container + Bottle A (1 unit) --> 4.27 kg
Container + Bottle B (3 units) --> 6.58 kg

3 units - 1 unit --> 6.58 kg - 4.27 kg
2 units --> 2.31 kg
1 unit --> 2.31 kg divided by 2 units = 1.155 kg
1.155 kg --> 1.16 kg correct to 2 decimal places

Answer: 1.16 kg

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