Q&A - P5 Math

Academic support for Primary 5
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DaddyD
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Re: Q&A - P5 Math

Post by DaddyD » Tue Jul 12, 2016 9:02 pm

Thanks. Any idea on using the percentage method?

garlicmummy
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Re: Q&A - P5 Math

Post by garlicmummy » Wed Jul 13, 2016 1:24 am

DaddyD wrote:Thanks. Any idea on using the percentage method?
It's similar actually. But i will break it down further:

1st week
Chocolate chip cookies – 35%
Oatmeal cookies – 65%
Total – 100%

2nd week
Chocolate chip cookies
percentage increase 40/100 x 35% = 14%
Total - 35 + 14 = 49%

Oatmeal cookies
percentage decrease 5/100 x 65% = 3.25%
Total - 65 – 3.25 = 61.75%

Total % cookies baked in week 2 - 49 + 61.75 = 110.75%

Diff – 110.75% – 100% =10.75%

10.75% – 43
1% – 4
49% – 49 x 4 = 196 (Chocolate cookies)

ksraja69
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A Mathlympics Question

Post by ksraja69 » Tue Jul 19, 2016 9:24 am

4 men and 4 women are to be seated at round table for dinner.If the men and women take alternate seats, how many arrangements are possible?

S_Mummy
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Re: Q&A - P5 Math

Post by S_Mummy » Tue Jul 19, 2016 11:24 am

Hi, please help. Thank you.

Johan had some $5 notes and $2 notes. The ratio of the number of $5 notes to the number of $2 notes was 6 : 11. When he exchanged 10 pieces of $5 notes for some $2 notes, the ratio of the number of $5 notes to the number of $2 notes became 2 : 7. How much money did Johan have altogether?

Ender
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Re: A Mathlympics Question

Post by Ender » Tue Jul 19, 2016 11:28 am

ksraja69 wrote:4 men and 4 women are to be seated at round table for dinner.If the men and women take alternate seats, how many arrangements are possible?
Is the answer 1152?


Nebbermind
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Re: Q&A - P5 Math

Post by Nebbermind » Tue Jul 19, 2016 11:37 am

S_Mummy wrote:Hi, please help. Thank you.

Johan had some $5 notes and $2 notes. The ratio of the number of $5 notes to the number of $2 notes was 6 : 11. When he exchanged 10 pieces of $5 notes for some $2 notes, the ratio of the number of $5 notes to the number of $2 notes became 2 : 7. How much money did Johan have altogether?
Before

No. of $5 = 6U
No. of $2 = 11U

After

(1) No. of $5 = 6U - 10 = 2P
(2) No. of $2 = 11U + 25 = 7P (10 * $5 can exchange for 25 * $2)

From (1), P = 3U - 5

Substitute 7P or 7*(3U - 5) into (2) and you can find U.

From there you can total up the $5 (6U) and $2 (11U)

Ender
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Re: Q&A - P5 Math

Post by Ender » Tue Jul 19, 2016 11:44 am

S_Mummy wrote:Hi, please help. Thank you.

Johan had some $5 notes and $2 notes. The ratio of the number of $5 notes to the number of $2 notes was 6 : 11. When he exchanged 10 pieces of $5 notes for some $2 notes, the ratio of the number of $5 notes to the number of $2 notes became 2 : 7. How much money did Johan have altogether?
First we find out how many pieces of $2 notes he gains, when he exchange for 10 pieces of $5.
10 x $5 = $50
Number of $2 =50/2= 25 pieces

6u -10 = 2p ---------> 42u-70 = 14p
11u+25 = 7p -------->22u+50 = 14p


42u - 70 = 22u + 50
20u = 120
u = 6

$5 notes =>6u => 36pcs, value = $180
$2 notes =>11u => 66pcs, value = $132

Total = $312

EconsPhDTutor
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Re: A Mathlympics Question

Post by EconsPhDTutor » Tue Jul 19, 2016 11:52 am

ksraja69 wrote:4 men and 4 women are to be seated at round table for dinner.If the men and women take alternate seats, how many arrangements are possible?
Fix any man in place (call him Man #1). To his left is a woman (4 possible choices) --- call her Woman #1. To her left is a man (3 possible choices) --- call him Man #2. To his left is a woman (3 possible choices) --- call her Woman #2. Etc.

Altogether, there are 4 × 3 × 3 × 2 × 2 × 1 × 1 = 144 possible arrangements.

Hope this helps and feel free to ask for any clarifications.

- Dr. Choo Yan Min

www.EconsPhDTutor.com

If you found this answer helpful, then please help me out by spreading word of my services. I’m a new tutor in Singapore so I need some help getting word out! Thank you!

S_Mummy
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Re: Q&A - P5 Math

Post by S_Mummy » Tue Jul 19, 2016 12:10 pm

Thank you very much, Ender & Nebbermind

S_Mummy
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Re: Q&A - P5 Math

Post by S_Mummy » Wed Jul 20, 2016 8:10 am

Please help with below Q.
Thank you.

Adele spent 60% of her money on 5 similar files and 6 similar markers. She bought another 4 similar markers with her remaining money and had $7 left.
How much did each file cost?

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