hey Vanilla Cake

all the best for your exams too!

Hi, please help if you can?


Water from 3 taps was used to fill an empty water tank. Tap X, Tap Y, Tap Z could fill the tank completely in 3 hours, 4 hours, 5 hours respectively.
(a) What fraction of the tank was filled with water after half an hour when all taps were turned on at the same time? Give your answer in the simplest form.

Now, only Tap X and Tap Y were both turned on to fill another empty water tank. Immediately after 20 minutes, Tap Z was also turned on. Both Tap X and Tap Y were turned off at the same time after turning on for an hour and only Tap Z was left to fill the tank completely.
(b) How much longer would Tap Z take to fill the tank completely with water after both Tap X and Tap Y were turned off?
Express your answer in terms of hours in its simplest form.

(a) 47/120
(b) 1 & 5/12 h

Hi all,


Q15) Mr Tan had 130 durians and mangosteens. After he sold 2/3 of the durians and 2/5 of the mangosteens, he had 36 more mangosteens than durians left. How many fruits had he left in all?

Ans: 66

Q16) [Please help if you have the diagram] The figure below is made up of a circle, a triangle and two identical semicircles. The diameter of the circle is 8cm and the diameter of the semi circle is 4cm. Find the area of the shaded regions. (Take pi = 3.14)

Ans: 30.8 cm square

Q17) Ahmad and Halim together took 5 days to paint their house. If Ahmad and Halim took together for 2 days, followed by Ahamd working alone for 8 days, Halim will take 1 more day to complete the remaining work. How long will Ahmad take to paint the house all by himself?

Ans: 17.5

Q18) Tracy counted the number of 10cents coins, 20cents coins and 50cents coins in her piggy bank. The number of 10 cents coins was 24 more than the number of 50 cents coins. After spending 3/5 of the 10cents coins, 1/4 of the 20 cents coins and 18 50 cents coins, she had an equal number of 10 cents and 20 cents coins. The number of 50 cent coins now formed 40% of the remaining number of coins.
(a) How many 10 cents coins did Tracy have at first?
(b) How much did she spend in all?

Ans: 90, $16.80

Hi all

Please help if you can.

Q15) Study the number pattern below.
5 to power 2 = 5 x 5 =25
5 to power 3 = 5 x 5 x 5 = 125
5 to power 4 = 5 x 5 x 5 x 5 =625
5 to power 5 = 5 x 5 x 5 x 5 x 5 =3125
(a) In 5 to power 6 , what is the sum of the digits in the ones and tens place?
(b) What is the sum of the last 3 digits in 5 to power 15?
What is the sum of the last 4 digits in 5 to power 210?


Ans: 7,8,18

Q16) Country A and Country B took part in a Youth Game. From Country A, the ratio of the number of male supporters to the number of female supporters is 5: 6. From Country B, the ratio of the number of male supporters to the number of female supporters was 1:3. The total number of supporters from Country A is 1/4 of the total number of supporters from Country B.
(a) What is the ratio of the number of female supporters from Country A to the number of female supporters from Country B? Express your answer in the simplest forml
(b) After 4985 male supporters from both countries left, the percentage of all the female supporters became 78%. How many more male supporters from country B than country A were there at first?

Ans: 2:11, 5982

Hi there

Thanks for helping me with the 4 exam prelim papers.

Vanilla Cake,
I will try SCGS question paper again. The truth is I find all questions mind-boggling. Then I will post the questions if I have time.
Thanks for telling me the powerpoint tip but most of the times, I only have enough time to type the questions…working adult’s time is not as much as you like to think! Will do with people who know what I am referring and can respond. Otherwise, I will just have to make do with whatever I can, I guess.

Hi again


Does anyone know where to find the complete step by step solutions for SCGS Prelims. Not sure how you feel about it but I cannot do most of the questions in paper 2.

There’s also much discussion about prelims 2010. May I know where I can find them and find the solutions?

Thanks in advance !!!

Hi everyone again - please help


Q4)[There is a diagram so please help if you have it]
Each link of a chain has an outside length of 40cm, and the metal is 4cm thick.
The diagram below shows a chain which is made up of 4 links. Find the maximum length, in cm, of a chain which is made up of 10 links.

Ans: 328 cm

Q12) Figure 1 below shows a rectangular tank containing 6 cubes and filled with water to its brim. In figure 2, four cubes were removed from the same tank and the water level dropped by 4.5cm. After that, a certain amount of water was drained off the tank until the water level reaches the same height as the remaining cubes. Find the volume of water in the tank in Figure 2.

Ans: 720 cm cube

Q13) The figure below is made up of 4 shaded parts formed by a circle and an isosceles triangle XYZ. The circle has a diameter of 12 cm and in the triangle XYZ, XY = XZ = 13cm and YZ = 10cm.
(a) Calculate the perimeter of the shaded parts.
(b) Calculate the difference between shaded parts ‘A’ and ‘B’.

Ans:
(a) 73.70cm
(b) 26.55cm square

Q17)Mr Tan took 6 h to drive from Town A to Town B.
Mr Lim who started at the same time as Mr Tan, took 4 hours to drive from Town B to Town A. When they met each other, they were 48km away from the midpoit of Town A and Town B.
(a) Calculate the distance between Town A and Town B.
(b) Calculate the speed of Mr Tan.

Ans:
(a) 480km
(b)80km/hour


Q18) 20% of John’s savings is $120 more than 30% of Brian’s savings. After John spent 5/6 of his savings and Brian spent 1/2 of his savings, John has $20 more than Brian. Find the savings of John at first.

Ans:
$1080

Hi everyone - please help if you can.


Q7) The figures below, X and Y, are 2 identical isoceles triangles. Both figures contain a square of a different size. Given that the area of the square in Figure X is 360 cm square, find the area of the sqaure in Figure Y.

Ans: 320 cm square

Q9) [This question has a picture. Please help if you can.]
The figure below is not drawn to scale. PQRS is a square and CBRD is a rectangle. BRE is a straight line. Given that angle DRF= 136 degree and angle SHD = 129, find the ratio of angle HRB to angle ERF.

Ans: 51:46

Q15) A bullet train took 5 hours to travel from Patient Town to Honest Town while an electric train took 4 hours to travel from Honest Town to Patient Town. Both trains set off at the same time and moved towards each other. Two hours later, they were 255 km apart. What was the speed of the electric train?

Ans: 75 km/h

Hi everyone - please help if you can.


Q6) Mrs Siva has some sweets. If she gives 5 sweets to each of her pupils, she will have 4 sweets left. If she gives 12 sweets to each of her pupils, she will need 73 more sweets. How many pupils are there?

Ans:
4 + 73 = 77
12 - 5 = 7
Pupils -> 77 / 7 = 11
There are 11 pupils. [I don’t understand the rationale.]


Q9) Find the value of
(3 + 5 + 7 + … + 21) / (40 + 60 + 80 + … + 360)

Ans: 3/85

Q13) The ratio of $2 notes to $5 notes in Joan’s piggy bank was 13: 8. She exchanged 20 pieces of $2 notes for some $5 notes, after which, the ration of $2 notes to $5 notes became 4:5. What was the total value of $2 notes and $5 notes in the piggy bank at first?

Ans: $264

Q15) [This question contains a picture. Please help if you have it.]
The figure below consists of 2 identical semicircles, a larger semicircle and a circle. The diameter of the big semicircle is 40cm. Find the shaded area. (Take pi = 3.14)

Ans: 228 cm square

Q16) The figure below shows a solid made up of 10 identical cubes. When the solid is painted black the total area being painted is 360 cm square.
(a) What is the volume of the solid?
(b) How many more cubes must be added to change this solid into a big cube with a volume of 729 cm cube?

Ans: (a) Volume is 270 cm cube.
(b) 17 cubes must be added.

Hi everyone - please help


Q6) Muthu and Beng Huat had some money. If Muthu gave Beng Huat $360. both would have an equal amount of money. If Beng Huat gave Muthu $180, Beng Huat would have 1/3 as much money as Muthu.
(a) How much money did Muthu have?
(b) How much money did Beng Huat have?

Ans:(a) $1440 (b) $720


Q9) Mr Kuah, a canteen vendor, had a container completely filled with oil. On the first day, he used 1 litre more than 1/2 of the original amount of oil in the container for his cooking. On the second day, he used 2 litres more than 1/3 of the remaining oil in the container. On the third day, he used 6 litres more than 1/7 of the oil left in the container. In the end, there were still 6 litres of oil in the container.
How many litres of oil were there in the container at first?

Ans: 50 litres


Q12) Given that p : (q+r)=1:3, r : (q+s)=1: 2 and p : s=2 : 5.
(a) p:q:r:s
(b) Find (r+q) : (p+s)

Ans:
(a) 6 : 7 : 11 : 15
(b) 6 : 7


Q16) [There is a diagram for this question. Please help if you have it]
The figure below consists of three circles. The smallest circle has centre O and radius of 4cm. The biggest circle has centre O and radius of 10cm. The diameter of the biggest circle also cuts through the centre of the medium-sized circle. The medium-sized circle touches the other two circles as shown. The three regions formed are coloured red, white and blue as shown.
(a) Find the radius of the medium-sized circle.
(b) Find the area of the white region. Use a calculator to obtain the value of pi. (Give your answer correct to 2 decimal places.)
Express the area of the red region as a fraction of the area of the blue region.


Ans:
(a) 7cm (b) 103.67cm square 16/51


Q17)Ahmad started travelling from Town P towards Town Q at 7am. After travelling for some time, he passed Steve who was travelling at an average speed of 80km/h in the opposite direction. After travelling for another 2 hours, Ahmad reached Town Q while Steve was still 40km away from Town P.
(a) If Ahmad reached Town Q at 1pm, what was his average speed?
(b) If Steve started his journey from Town Q, at what time did he leave Town Q?

Ans
(a) 50 km/hour
(b) 9.45a.m.

Q18)Mdm Ang bought some highlighters, pens and mechanical pencils. 1/4 of them were highlighters. The number of pens she bought was 6 more than 1/2 the total number of all the items and the remaining were mechanical pencils. Each of the highlighters, pens and mechanical pencils cost $2.10, $4.05, $1.60 respectively. She spent a total of $227. 10 on all the items. How many pens did she buy altogether?

Ans:
42