## Q&A - P4 Math

### Re: Q&A - P4 Math

Hi can someone help me with this sum ? TIA!!!

Mrs Lim had 240 eggs. She threw away 1/3 of them which were rotten and sold 7/8 of the good

eggs. How many eggs did she have left?

Mrs Lim had 240 eggs. She threw away 1/3 of them which were rotten and sold 7/8 of the good

eggs. How many eggs did she have left?

- PiggyLalala
- KiasuGrandMaster
**Posts:**4053**Joined:**Tue May 24,**Total Likes:**23

### Re: Q&A - P4 Math

Rotten eggs =1/3×240=80.mumof8 wrote:Hi can someone help me with this sum ? TIA!!!

Mrs Lim had 240 eggs. She threw away 1/3 of them which were rotten and sold 7/8 of the good

eggs. How many eggs did she have left?

Good eggs = 240-80=160.

7/8 of the good eggs were sold= 1/8 of the good eggs were unsold

leftover eggs =1/8×160 = 20

### P4 Maths

Need some help on this, please

Mr Lim has some pencils. If he ties them in bundles of 6 he will have 5 extra pencils. If he ties them in bundles of 5 he will be short of 3 pencils. What is the smallest possible number of pencils mr Lim has?

I am not sure why I can't get the answer by using the shortage + excess formula to do this and why this is different to using the multiple working solution?

Formulae 5+3=8, 6-5=1, 8/1=8

8*5=40, 40-3=37 but correct answer is 17??

Mr Lim has some pencils. If he ties them in bundles of 6 he will have 5 extra pencils. If he ties them in bundles of 5 he will be short of 3 pencils. What is the smallest possible number of pencils mr Lim has?

I am not sure why I can't get the answer by using the shortage + excess formula to do this and why this is different to using the multiple working solution?

Formulae 5+3=8, 6-5=1, 8/1=8

8*5=40, 40-3=37 but correct answer is 17??

- sky minecrafter
- KiasuGrandMaster
**Posts:**2253**Joined:**Sat Jun 27,**Total Likes:**69

### Re: P4 Maths

Hi,Chan09 wrote:Mr Lim has some pencils. If he ties them in bundles of 6 he will have 5 extra pencils. If he ties them in bundles of 5 he will be short of 3 pencils. What is the smallest possible number of pencils mr Lim has?

I am not sure why I can't get the answer by using the shortage + excess formula to do this and why this is different to using the multiple working solution?

Formulae 5+3=8, 6-5=1, 8/1=8

8*5=40, 40-3=37 but correct answer is 17??

This came from 2015 RGS?

NOT 5+3, since u r short of 3, it actually means u've 2 more. Instead of shortage+excess (which is great), I use e listing method.

List the multiples.

Multiples of 6+5: 11, 17...

Multiples of 5+2: 7, 12, 17...

Answer: 17 pencils (QED)

- PiggyLalala
- KiasuGrandMaster
**Posts:**4053**Joined:**Tue May 24,**Total Likes:**23

### Re: P4 Maths

I think the shortage and excess method cannot work because the number of bundles are different in the 2 cases.Chan09 wrote:Need some help on this, please

Mr Lim has some pencils. If he ties them in bundles of 6 he will have 5 extra pencils. If he ties them in bundles of 5 he will be short of 3 pencils. What is the smallest possible number of pencils mr Lim has?

I am not sure why I can't get the answer by using the shortage + excess formula to do this and why this is different to using the multiple working solution?

Formulae 5+3=8, 6-5=1, 8/1=8

8*5=40, 40-3=37 but correct answer is 17??

### P4 question

Plse help as I don't get the same answer using the excess shortage formulas vs doing this using multiple:

Mr lim has some pencils. If he ties them in bundles of 6 he will have 5 extra pencils. If he ties them in bundles of 5 he will be short of 3. What is the smallest possible number of pencils he has?

If I use excess shortage formulae : 5+3=8, difference 6 -5=1, then 8/1=8, 8*5=40, 40-3=37 but using multiple method the answer is 17. Plse advise, tks

Mr lim has some pencils. If he ties them in bundles of 6 he will have 5 extra pencils. If he ties them in bundles of 5 he will be short of 3. What is the smallest possible number of pencils he has?

If I use excess shortage formulae : 5+3=8, difference 6 -5=1, then 8/1=8, 8*5=40, 40-3=37 but using multiple method the answer is 17. Plse advise, tks

### Re: P4 question

"5 extra" means "short of 1" and "short of 3" means "extra 2".

111111

11111

Which color is "short" and which color is "extra" is only a matter of perspective.

Therefore 3 imaginary bundles of pencils, ie. 3x6-1=17 or 3x5+2=17.

PS: Somebody already asked this exact question in the other thread. Would be nice if the Mods merge this and the other thread into the P4 Maths thread.

111111

11111

Which color is "short" and which color is "extra" is only a matter of perspective.

Therefore 3 imaginary bundles of pencils, ie. 3x6-1=17 or 3x5+2=17.

PS: Somebody already asked this exact question in the other thread. Would be nice if the Mods merge this and the other thread into the P4 Maths thread.

### Re: P4 question

I am under the impression that excess shortage formula isChan09 wrote:Plse help as I don't get the same answer using the excess shortage formulas vs doing this using multiple:

Mr lim has some pencils. If he ties them in bundles of 6 he will have 5 extra pencils. If he ties them in bundles of 5 he will be short of 3. What is the smallest possible number of pencils he has?

If I use excess shortage formulae : 5+3=8, difference 6 -5=1, then 8/1=8, 8*5=40, 40-3=37 but using multiple method the answer is 17. Plse advise, tks

applicable only when there is a fixed number of sets?

Eg. Ms Chan gave 5 sweets to each of her students and had 5 extra.

When she gave them 6 sweets each, she was short of 3.

In the example above, the number of sets (students) does not change from

the first scenario to the second.

But in the question which you asked, the number of sets changed from

2 bundles of 6 pencils + 5 extra to

3 bundles of 5 pencils + 2 extra

Hence applying excess shortage formula in this situation is not correct.

Just my opinion...dunno if there's a variation of the formula

which can be used for such question.