## Q&A - P5 Math

- garlicmummy
- OrangeBelt
**Posts:**33**Joined:**Sun Nov 22,

### Re: Q&A - P5 Math

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

**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)

### A Mathlympics Question

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?

### Re: Q&A - P5 Math

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?

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?

### Re: A Mathlympics Question

Is the answer 1152?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?

- Nebbermind
- KiasuGrandMaster
**Posts:**16343**Joined:**Tue Dec 22,**Total Likes:**161

### Re: Q&A - P5 Math

BeforeS_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?

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)

### Re: Q&A - P5 Math

First we find out how many pieces of $2 notes he gains, when he exchange for 10 pieces of $5.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?

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
- OrangeBelt
**Posts:**39**Joined:**Sat Jan 23,**Total Likes:**1

### Re: A Mathlympics Question

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.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?

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

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### Re: Q&A - P5 Math

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?

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?