Rosyth boy tops PSLE

http://www.straitstimes.com/BreakingNews/Singapore/Story/STIStory_607535.html

ALEX Tan Kian Hye of Rosyth School is the top Primary School Leaving Examination (PSLE) pupil this year with a score of 282.

Fu Wan Ying from Tao Nan School had the second highest score of 279.

The top Malay pupil is Aquilah Dariah Mohd Zulkarnain, of Coral Primary School who scored 278, while the top Indian pupil is Muhammad Hameem, of Henry Park Primary School with a score of 274, and the top Eurasian pupil is Lendermann Monika Jiz-xin, of CHIJ Our Lady Queen of Peace, with a 269 score.

Top PSLE 2010 Score - 282 (unofficial)

News from Kiasu Parents Forum.

Top Score - 282
School - Rosyth

Above is unofficial.

Year 2011 Classes

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Classes and Subjects (Small group tuition)

Primary 1 and 2 - English, Maths
Primary 3 to 6 - English, Maths, Science

We will be starting classes early or mid November.


Taught by a husband and wife team.

Home based tuition, located at Tampines, along Tampines Avenue 5.

For enquiries, you may call Mrs Song at

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RGS Primary 2009 PSLE Math Prelim Paper 2 Q18

At first, 25% of Kumar's money was the same as 33 and 1/3 % of Lily's money. Lily's father gave her $80 later, while Kumar spent $325. In the end, Lily had 2 and 1/2 times as much money as Kumar.

a) How much money did Kumar have at first?

b) How much money did Lily have in the end?

Solution

(Kumar) 4 units --> 2 parts + 325 (x5)**

(Lily) 3 units + 80 --> 5 parts (x2)**

**Kumar (x5) and Lily (x2) to make both of them 10 equal parts each.

(K) 20 units --> 10 parts + 1625

(L) 6 units + 160 --> 10 parts

(K) 20 units --> 10 parts + 1625

(L) 6 units --> 10 parts - 160

(K) - (L)

20 units - 6 units --> 10 parts - 10 parts + 1625 - (-160)

14 units --> 1625 + 160

14 units --> 1785
1 unit --> 1785 divided by 14 = 127.5

(a)

Kumar at first

4 units --> 4 x 127.5 = 510

Answer: $510

(b)
Lily in the end
--> 3 units + 80
(3 x 127.5) + 80
= 382.5 + 80
= 462.5

Answer: $462.50

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RGS Primary 2009 PSLE Math Prelim Paper 2 Q17

At 9.30 am, Train A which was 200 m long, pulled out of Nanas Station and travelled towards Dadas Station at a uniform speed of 80 km/h. Half an hour later, Train B which was 150 m long, left Dadas Station and travelled towards Nanas Station at a uniform speed of 90 km/h.

a) How far has Train A travelled when Train B left Dadas Station?

b) The two trains met each other in a tunnel. Both trains took 15 minutes to completely travel through the tunnel. Calculate the length of the tunnel.

Solution

a)

Distance = speed x time

= 80 km/h x (1/2) hour

= 40 km

Answer: 40 km

b)

(Train A) distance

= 80 km x (1/4) hr

= 20 km

(Train B) distance

= 90 km x (1/4) hr

= 22.5 km

Length of Tunnel

--> 20km + 22.5km - 0.2km (Train A's length) - 0.15km (Train B's length)

= 42.15 km

Answer: 42.15 km

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RGS Primary 2009 PSLE Math Prelim Paper 2 Q16

There were some sweets in Boxes X, Y and Z. Box X contained 20% of the total number of sweets in Boxes X, Y and Z. The ratio of the number of sweets in Box Y to the total number of sweets in Boxes X and Z is 2:1. If there are 24 more sweets in Box Y than Box Z, find the total number of sweets in Boxes X, Y and Z.

Solution

Box X --> 20% of total sweets
= 20/100
= 1/5 --> (3/15) of total sweets

Box Y --> 2 units
Box X + Z --> 1 unit
(Total 3 units)

Box Y --> (2 units)/(3 units)
= 2/3 --> (10/15) of total sweets

Z --> 2 units
Y - Z --> 24 sweets
10 units - 2 units --> 24 sweets
8 units --> 24 sweets
1 unit --> 24 sweets divided by 8 = 3 sweets
15 units --> 15 x 3 sweets = 45 sweets

Answer: 45 sweets

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RGS Primary 2009 PSLE Math Prelim Paper 2 Q15

The equilateral triangles below are formed using 2 cm sticks.

a) How many sticks are needed to form Pattern 5?
b) In which pattern will each side of the triangle measure 30 cm?
c) Calculate the number of shaded triangles in Pattern 100.

Solution

b)
Pattern 1 --> 1 x 2cm = 2 cm
Pattern 2 --> 2 x 2cm = 4 cm
Pattern 3 --> 3 x 2cm = 6 cm
:
:
:
Pattern 15 --> 15 x 2cm = 30 cm

Answer: Pattern 15

From above
1 + 2 + 3 ..... + 100

1 + 99 = 100
2 + 98 = 100
3 + 97 = 100
:
:
49 + 51 = 100
(only 50 is not paired)

49 groups of 100 --> 4900
Add the unpaired 50 --> 4900 + 50 = 4950

Answer: 4950 shaded triangles

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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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RGS Primary 2009 PSLE Math Prelim Paper 2 Q13

The figure below is made up of a big circle, square and a small circle. The area of the square is 400 square cm. Find the area of the shaded region. (Correct your answer to 2 decimal places)

Solution

Area of square --> 400 square cm
Length of square --> 20 cm (square root of 400 sq cm)

Area of 1/4 square

--> 400 square cm divided by 4

= 100 square cm

Area of one right-angle triangle -->(1/2)(b)(h)

100 square cm = (1/2)(r)(r)

(r)(r) = (100 square cm) x 2 = 200 square cm

Area of circle = (3.14)(r)(r)

=(3.14)(200 square cm)

= 628 square cm

Shaded area -->(628 - 400) square cm

= 228 square cm
= 228.00 square cm (correct to 2 decimal places)

Answer: 228.00 square cm

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RGS Primary 2009 PSLE Math Prelim Paper 2 Q12

Tap A, Tap B, Tap C and an empty rectangle tank are shown below.

Lily turned on Tap A with water flowing at a rate of 5 litres per minute. After 2 minutes, she placed a rock of volume 1250 cubic cm in the tank and turned on Tap B and Tap C as well. Tap C drains the tank at the rate of 2 litres per minute. After 5 more minutes, Lily turned off all the taps and noted that the height of the water level was 30 cm. Find the rate of the flow of water from Tap B.

Solution

Tap A (water filled into tank)

--> 5 litres x 7 (min) = 35 litres

Tap B (water drained from tank)

-->2 litres x 5 (min) = 10 litres

Volume of water in tank in the end

--> (50 x 30 x 30) cubic cm - 1250* cubic cm

= (45 000 - 1250) cubic cm

= 43 750 cubic cm

* volume of stone

43 750 cubic cm is the total volume of water filled through Tap A and Tap B less the volume of water drained from Tap C.
Tap A + Tap B - Tap C --> 43 750 ml

Tap B --> 43 750 ml - Tap A + Tap C
= 43 750 ml - 35 000 ml + 10 000 ml

= 18 750 ml (after 5 min)

1 min --> 18 750 ml divided by 5

= 3750 ml/min

= 3.75 litres/min

Answer: 3.75 litres/min

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