Q&A - PSLE Math

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

Post by xoxoxo » Sun Sep 21, 2014 8:27 pm

[quote="Kangkangteo"][quote="speedmaths.com"][quote="Kangkangteo"][quote="xoxoxo"]Please Help!

John spent $4968 on bags and shoes. The number of pairs of shoes he bought
was ²/₅ the number of bags he bought. The cost of a pair of shoes was [b][u][color=#FF0000]$12 more[/color][/u][/b] than the cost of a bag. He paid $1512 more on bags than on shoes.
Find the cost of a bag.[/quote]

2u + 5p ---> $4968

5p - 2u ---> $1512

10p ---> 4968 + 1512 = $6480

1p ---> 6480/10 = $648 (ans)[/quote]

Hi,

You need to account for the [color=#FF0000][b][u]$12[/u][/b][/color] bit.

Cheers

[b][color=#FF0000]
speedmaths[/color][/b][/quote]

The extra information given is redundant. [3 equations and 2 unknowns]

If you solve for 1u, you will get 1u - 1p = $12.[/quote]


Hi,

1u - 1p = $216

$216 / $12 = 18 (items per box/container)

$648 / 18 bags = $36 per bag (ans)


Cheers


Speedmaths

Thanks.

I will amend the original posting.

Kangkangteo
.[/quote][/quote]


Thanks Kangkangteo for your help but the answer given is $90.

jjxy mum
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Re: Q&A - PSLE Math

Post by jjxy mum » Sun Sep 21, 2014 9:12 pm

Can someone help?

Image

Kangkangteo
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Re: Q&A - PSLE Math

Post by Kangkangteo » Sun Sep 21, 2014 9:33 pm

quote="xoxoxo"quote="Kangkangteo"
speedmaths.com wrote:
Kangkangteo wrote:
xoxoxo wrote:Please Help!

John spent $4968 on bags and shoes. The number of pairs of shoes he bought
was ²/₅ the number of bags he bought. The cost of a pair of shoes was $12 more than the cost of a bag. He paid $1512 more on bags than on shoes.
Find the cost of a bag.
2u + 5p ---> $4968

5p - 2u ---> $1512

10p ---> 4968 + 1512 = $6480

1p ---> 6480/10 = $648 (ans)
Hi,

You need to account for the $12 bit.

Cheers


speedmaths
The extra information given is redundant. [3 equations and 2 unknowns]

If you solve for 1u, you will get 1u - 1p = $12.[/quote]


Hi,

1u - 1p = $216

$216 / $12 = 18 (items per box/container)

$648 / 18 bags = $36 per bag (ans)


Cheers


Speedmaths

Thanks.

I will amend the original posting.

Kangkangteo



Thanks Kangkangteo for your help but the answer given is $90.[/quote]


Sorry, the number of bags is 90. The cost of each bag is confirmed to be $36.

Kangkangteo

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Re: Q&A - PSLE Math

Post by Kangkangteo » Sun Sep 21, 2014 9:41 pm

jjxy mum wrote:Can someone help?

Image
...........|<-------- 30 ------------>|
C |_|_|_|_|_|_|_|_|_|_|_|_|3|
D |_|_|_|_|_|_|

9u + 3 ---> 30

1u ---> 27/9 = 3

C : 3u + 30 ---> 3 x 3 + 30 = 39 chocolates (ans a)

D : 6u ---> 3 x 6 = 18 chocolates (ans b)

speedmaths.com
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Re: Q&A - PSLE Math

Post by speedmaths.com » Sun Sep 21, 2014 10:33 pm

Kangkangteo wrote:
Trevortan wrote:2. The average length of 6 ropes was 80 cm. The average length of 4 of the ropes A, B, C and D was 15 cm more than the average length of the remaining 2 ropes E and F. If Rope E had been 18 cm shorter and Rope F had been 12 cm longer, they would have been of the same length. Find the actual length of Rope E.
A+B+C+D ----> 4u + 15 x 4 = 4u + 60

E ---> 1u + 18

F ---> 1u - 12

6u + 66 ---> 80 x 6 = 480

6u ---> 480 - 66 = 414

1u ---> 414/6 = 69

69 + 18 = 87 cm (ans)
Hi,

Please check:

Answer sh be 85 cm.

Cheers



SpeedMaths


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Re: Q&A - PSLE Math

Post by Kangkangteo » Mon Sep 22, 2014 9:15 am

speedmaths.com wrote:
Kangkangteo wrote:
Trevortan wrote:2. The average length of 6 ropes was 80 cm. The average length of 4 of the ropes A, B, C and D was 15 cm more than the average length of the remaining 2 ropes E and F. If Rope E had been 18 cm shorter and Rope F had been 12 cm longer, they would have been of the same length. Find the actual length of Rope E.
A+B+C+D ----> 4u + 15 x 4 = 4u + 60

E ---> 1u + 18

F ---> 1u - 12

6u + 66 ---> 80 x 6 = 480

6u ---> 480 - 66 = 414

1u ---> 414/6 = 69

69 + 18 = 87 cm (ans)
Hi,

Please check:

Answer sh be 85 cm.

Cheers



SpeedMaths
Thanks. I have amended the original posting.

Anurya301
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Re: Q&A - PSLE Math

Post by Anurya301 » Mon Sep 22, 2014 9:37 am

Hi , Im finding it difficult to upload . Don't know what is wrong. Moms pl help. [IMG]http://i61.tinypic.com/11mcg92.jpg[/IMG]

adribaby
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Re: Q&A - PSLE Math

Post by adribaby » Mon Sep 22, 2014 9:47 am

Hi. Is it compulsory to write final statements in all problem sum questions.?

Thanks.

lulu2014
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Re: Q&A - PSLE Math

Post by lulu2014 » Mon Sep 22, 2014 10:09 am

need help with these qns. thanks.

1) The number of boys was 4/5​ the number of girls in the library at first.
After 20 girls left the library and 6 boys came, there was an equal number of boys and girls in the library. How many girls were there in the library at first?

2) Eddie, Freddie and Georgie had some stickers. Eddie gave 20% of his stickers to Freddie. Freddie in turn gave 20% of his stickers to Georgie. In the end, Georgie's stickers increased by 20%. If Eddie and Georgie had 16 and 42 stickers respectively in the end, how many stickers did the three boys have altogether?

3) There were 250 more adults than children on an aeroplane. At a particular airport, 20% of the children alighted. The ratio of the number of adults who alighted to the number of adults who remained was 2 : 3. In the end, there were 30 more children than adults on the aeroplane. How many adults were there on the aeroplane in there?

Kangkangteo
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Re: Q&A - PSLE Math

Post by Kangkangteo » Mon Sep 22, 2014 11:08 am

lulu2014 wrote:need help with these qns. thanks.

1) The number of boys was 4/5​ the number of girls in the library at first.
After 20 girls left the library and 6 boys came, there was an equal number of boys and girls in the library. How many girls were there in the library at first?

B |____|____|____|____|6|
G |____|____|____|____|____|
G |____|____|____|____|6|20|

1u ---> 6 + 20 = 26

6u ---> 26 x 6 = 156 girls (ans)

2) Eddie, Freddie and Georgie had some stickers. Eddie gave 20% of his stickers to Freddie. Freddie in turn gave 20% of his stickers to Georgie. In the end, Georgie's stickers increased by 20%. If Eddie and Georgie had 16 and 42 stickers respectively in the end, how many stickers did the three boys have altogether?

E ........... F .......... G ........... (Checking
------------------------------
25u ...... 5p ...... 5u+5p ....... (20,,31,,35
-5u .... +5u .........................(-4,,+4
------------------------------
20u .. 5u+5p ..... 5u+5p ..... (16,,35,,35
........ -1u-1p .... +1u+1p ....(....,,-7,,+7
-------------------------------
20u .. 4u+4p ..... 6u+6p .....(16,,28,,42
-------------------------------

20u ---> 16
1u ---> 16/20 = 0.8

30u ---> 0.8 x 30 = 24

6u + 6p ----> 42

6p ---> 42 - 0.8 x 6 = 37.2

1p ---> 37.2/6 = 6.2

10p ---> 6.2 x 10 = 62

62 + 24 = 86 (ans)


3) There were 250 more adults than children on an aeroplane. At a particular airport, 20% of the children alighted. The ratio of the number of adults who alighted to the number of adults who remained was 2 : 3. In the end, there were 30 more children than adults on the aeroplane. How many adults were there on the aeroplane in therethe end?????

A |____||____||____||____||____||_150_||100|
C |____||____||____||____||____|

1u - 150 ---> 30

1u ---> 30 + 150 = 180

3u + 150 ----> 180 x 3 + 150 = 690 adults in the end

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