Q&A - PSLE Math

Academic support for Primary 6 and PSLE
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tutor76
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Re: Q&A - PSLE Math

Post by tutor76 » Tue Apr 05, 2016 4:15 pm

Anyone heard of the 3/4 pi d formulae to calculate perimeter of a semicircle ?

SOS mum
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Re: Q&A - PSLE Math

Post by SOS mum » Tue Apr 05, 2016 8:24 pm

sushi88 wrote:
SOS mum wrote:Ps help the following qns. Many tks and God Bless:)

(1) The total number of game cards that Fandi and Geetha had was the same as the number that Eugene had. The total number of game cards that Eugene and Geetha had was 5 times the number that Fandi had.
(a) What was the ratio of the number of game cards that Eugene had to the number of game cards that Geetha had to the number of game cards that Fandi had?
(b) Eugene had 118 game cards more than Fandi. How many game cards did the 3 children have altogether?
Alternative method using diagram.

Image
Thank u very much, Sushi88

SOS mum
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Re: Q&A - PSLE Math

Post by SOS mum » Tue Apr 05, 2016 8:42 pm

Hi, ps help. Many thks and God Bless:)

1) Irene, Doreen, Shawnia and Ruth made some balloons. Doreen made 252 balloons at first. Ruth donated some of her balloons and her number of balloons decreased by 20%. Irene made another 40% of her balloons. Shawnia gave away 30 fewer balloons than what Doreen had made. In the end, they had an equal number of balloons. How many balloons did they make altogether at first?

2) In a bakery shop, there are some curry, sardine and kaya buns. There are 216 more curry than sardine buns. There is 3 times as many curry as kaya buns. There is 12% as many sardine buns as the total number of buns. How many buns are there in the bakery shop?

(3) Mrs Letilia made 45 fewer dumplings than Mrs Hagans. Mrs Hagans decided to give 20% of her dumplings to Mrs Letilia. Mrs Letilia then gave 2/3 of her dumplings to Mrs Hagans. In the end, Mrs Hagans had 69 more dumplings than Mrs Letilia. How many dumplings did Mrs Hagans give to Mrs Letilia?

SOS mum
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Re: Q&A - PSLE Math

Post by SOS mum » Tue Apr 05, 2016 8:58 pm

Sorry, some more qns:

At the Woodlands Checkpoint, there were 24 more cars than lorries waiting at the gantry for clearance at first. After 2/3 of the cars and 20% of the lorries had cleared the gantry, there were 20 fewer cars than lorries waiting at the gantry. How many cars had cleared the gantry?

(2) Mrs Sharee bought a total of 38 cups and saucers for her upcoming party. She bought 10 more cups than saucers. The cost of a saucer was 2/9 of the total cost of a cup and a saucer. Given that she paid a total of $215.60 for all the cups and saucers, what was the cost of a cup?

SOS mum
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Re: Q&A - PSLE Math

Post by SOS mum » Tue Apr 05, 2016 9:14 pm

Mrs Wong prepared some orange syrup in a large pot. She transferred 60% of the syrup into an empty bottle. 75% of the remaining syrup was poured in to a mug leaving 210 litres of syrup left in the pot. Given that the bottle was 70% full, how much more would Mrs Wong need to prepare to fill up the bottle completely?

2) Yvonne, Maple and Florence were given an equal number of pins to decorate their rooms. Yvonne used 60% of her pins, Florence used 20% more pins than Yvonne and Maple used 48 pins. Given that they had a total of 78 pins left, how many pins were given to each of them at first?

3) There are 15 fewer rings than bracelets in a shop. There is 21 more bracelets than necklaces. There is 23 more hairclips than rings. There is 2/9 as many necklaces as bracelets and hairclips. How many rings are there in the shop?


origami
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Re: Q&A - PSLE Math

Post by origami » Tue Apr 05, 2016 10:08 pm

Last year, there were 375 volunteers for a sports event. This year, the number of male volunteers increased by 20% and the number of female volunteers increased by 30%. In the end, there was an equal number of. Male and female volunteers this year. How many female volunteers joined this year?

Thank you very much!!

Ender
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Re: Q&A - PSLE Math

Post by Ender » Tue Apr 05, 2016 10:36 pm

SOS mum wrote:Mrs Wong prepared some orange syrup in a large pot. She transferred 60% of the syrup into an empty bottle. 75% of the remaining syrup was poured in to a mug leaving 210 litres of syrup left in the pot. Given that the bottle was 70% full, how much more would Mrs Wong need to prepare to fill up the bottle completely?
After she transferred 60% to a bottle, there will be 40% left in the pot.

75% of the remainder 40%, is also 3/4 of the remainder 40%. 3/4 of the 40% remainder went to the mug means 30% went into the mug, and 10% left in the pot.
Therefore 10% => 210 litres.
60%=> 1260 litre, that's to the bottle.

70% of bottle = > 1260 litres,
She needs 30% more to fill up the bottle,
10% => 1260/7 = 180 Litres
30% = > 540 litres#

Jmaths.SG
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Re: Q&A - PSLE Math

Post by Jmaths.SG » Wed Apr 06, 2016 1:29 am

SOS mum wrote:Mrs Wong prepared some orange syrup in a large pot. She transferred 60% of the syrup into an empty bottle. 75% of the remaining syrup was poured in to a mug leaving 210 litres of syrup left in the pot. Given that the bottle was 70% full, how much more would Mrs Wong need to prepare to fill up the bottle completely?

2) Yvonne, Maple and Florence were given an equal number of pins to decorate their rooms. Yvonne used 60% of her pins, Florence used 20% more pins than Yvonne and Maple used 48 pins. Given that they had a total of 78 pins left, how many pins were given to each of them at first?

3) There are 15 fewer rings than bracelets in a shop. There is 21 more bracelets than necklaces. There is 23 more hairclips than rings. There is 2/9 as many necklaces as bracelets and hairclips. How many rings are there in the shop?
[1]
25% of remaining syrup = 210 litres
100% of remaining syrup = 840 litres

Since Remaining syrup = 40% of syrup,
40% of syrup = 840 litres
60% of syrup = 1260 litres

Since 60% of syrup = 70% of bottle,
70% of bottle = 1260 litres
30% of bottle = 540 litres

[2]
Y (used) = 60%
Y (unused) = 40%

F (used) = 120% of 60% = 72%
F (unused) = 28%

M (used) = 48
M (unused) = 100% - 48

Left = 40% + 28% + (100% - 48) = 78
168% = 126
100% = 75

[3]
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Jmaths.SG
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Re: Q&A - PSLE Math

Post by Jmaths.SG » Wed Apr 06, 2016 1:38 am

origami wrote:Last year, there were 375 volunteers for a sports event. This year, the number of male volunteers increased by 20% and the number of female volunteers increased by 30%. In the end, there was an equal number of. Male and female volunteers this year. How many female volunteers joined this year?

Thank you very much!!
Males (this yr) = 120% of Males (last yr)
Females (this yr) = 130% of Females (last yr)

Males (this yr) = Females (this yr)
Therefore,
120% of Males (last yr) = 130% of Females (last yr)
100% of Males (last yr) = 108 1/3 % of Females (last yr)

Males (last yr) + Females (last yr) = 375
108 1/3 % of Females (last yr) + 100% of Females (last yr) = 375
208 1/3 % of Females (last yr) = 375
30% of Females (last yr) = 54

Ender
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Re: Q&A - PSLE Math

Post by Ender » Wed Apr 06, 2016 2:14 pm

SOS mum wrote:Sorry, some more qns:

At the Woodlands Checkpoint, there were 24 more cars than lorries waiting at the gantry for clearance at first. After 2/3 of the cars and 20% of the lorries had cleared the gantry, there were 20 fewer cars than lorries waiting at the gantry. How many cars had cleared the gantry?
Let Lorry = 15L
C = 15L + 24

After 2/3 of the cars cleared the gantry, 1/3 of the cars is left
C2 = 5L + 8 ,From (15L+24)/3

After 20% of the Lorry cleared the gantry, 80% of the Lorry is left
L2 = 12L ,From 0.8 X 15L

L2 - C2 = 20
12L - 5L - 8 = 20
7L -8 = 20
7L= 28
L = 4

C = 15L +24 = 15(4) + 24 = 84
Car that cleared the gantry = 2/3 X 84 = 56#
SOS mum wrote: (2) Mrs Sharee bought a total of 38 cups and saucers for her upcoming party. She bought 10 more cups than saucers. The cost of a saucer was 2/9 of the total cost of a cup and a saucer. Given that she paid a total of $215.60 for all the cups and saucers, what was the cost of a cup?
Find number of cups and saucer. From simple modelling should derive the following equation.
Saucer = (38 -10) / 2 = 14
Cup = 24

Let the cost of one set of Saucer plus Cup be 9u,
Therefore each Saucer cost 2u and each Cup cost 7u. From saucer cost 2/9 of the total a cup + saucer

Total cost of Saucers = 14 X 2u = 28u
Total cost of Cups = 24 X 7u = 168u

Total cost = 168u + 28 u = 196u = $215.60
u = 1.1

One Cup = 7u = 7(1.1) = $7.70#
Last edited by Ender on Tue Apr 26, 2016 9:24 pm, edited 2 times in total.

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