Tutor MathsGuru: Ask me for your burning Maths questions!

[rrjan]

Could all the kind maths gurus kindly help me with this question? Its a P3 question. Sincere thanks


Mrs Lim buys 3 kg of beef and has $15 left. If she wants to buy 4 kg of beef, she would need $3 more. How much money does Mrs Lim have?

[MathIzzzFun]

rrjan:

Could all the kind maths gurus kindly help me with this question? Its a P3 question. Sincere thanks


Mrs Lim buys 3 kg of beef and has $15 left. If she wants to buy 4 kg of beef, she would need $3 more. How much money does Mrs Lim have?

Hi

reply posted at the P3 thread.

cheers.

[starry15]

Hi where is p3 thread? I’ve another question taken from p3 Onsponge. I’ve difficulty explaining to my gal. Hope to get some enlightenment here.


Miss Lim bought a packet of sweets to distribute to her class. If each child gets 3 sweets, she would be left with 30 sweets. If each child gets 5 sweets, she would need 5 more sweets.
A) how many children are there in her class?
B) how many sweets did Miss Lim have at first?

[MathIzzzFun]

starry15:

Hi where is p3 thread? I've another question taken from p3 Onsponge. I've difficulty explaining to my gal. Hope to get some enlightenment here.


Miss Lim bought a packet of sweets to distribute to her class. If each child gets 3 sweets, she would be left with 30 sweets. If each child gets 5 sweets, she would need 5 more sweets.
A) how many children are there in her class?
B) how many sweets did Miss Lim have at first?

Hi

You can post the P3 questions at this forum - http://www.kiasuparents.com/kiasu/forum/viewforum.php?f=66

Could you check the question - something is amiss...

The \"normal\" way to solve this type of question is to list out the multiples eg. 3,6,9,12 etc and then add 30 to the multiples, do the same for multiples of 5 and subtract 5 (there might be error in the question, it should be an even number - 30 + 5 = 35), and then find the total which tally for both for same number of children.


The question can also be looked from this perspective;
- I have 30 sweets to give to some children, if I were to give 2 sweets to each child, I would need 6 more. How many children were there ?

Total number of sweets needed = 30 + 6 = 36, number of children = 36/2 = 18

For the posted question.. we can assume that each child had 3 sweets, so for each child to get 5 sweets, each will get 2 more sweets - so it becomes similar to the above eg. except that the total number of sweets differ.

cheers.

[starry15]

MathizzFun,

My mistake. It should be :

Miss Lim bought a packet of sweets to distribute to her class. If each child gets 3 sweets, she would be left with 30 sweets. If each child gets 4 sweets, she would need 5 more sweets.
A) how many children are there in her class?
B) how many sweets did Miss Lim have at first?

The answer is 35 kids. Onsponge solution is that by adding 1 sweet per child = 30+5 sweets (short fall plus extra). Hence the answer is 35 kids. Using multiples may be very time consuming in this example so Onsponge solution is quick and accurate. But my problem is how to explaib to my gal. She gave me a blank look when I tried to explain :?:

[MathIzzzFun]

starry15:

MathizzFun,

My mistake. It should be :

Miss Lim bought a packet of sweets to distribute to her class. If each child gets 3 sweets, she would be left with 30 sweets. If each child gets 4 sweets, she would need 5 more sweets.
A) how many children are there in her class?
B) how many sweets did Miss Lim have at first?

The answer is 35 kids. Onsponge solution is that by adding 1 sweet per child = 30+5 sweets (short fall plus extra). Hence the answer is 35 kids. Using multiples may be very time consuming in this example so Onsponge solution is quick and accurate. But my problem is how to explaib to my gal. She gave me a blank look when I tried to explain :?:

Hi

Yes, answer is 35 kids..

What if the question is :
Ms Lim has 30 sweets to give her students. She would need 5 more sweets if each child were to get 1 sweet each. What is the answer ? .. this should be quite straightforward - 30+5 = 35 ... this is exactly the same reasoning applied to the above problem. Just imagined that each child had 3 sweets each, to give each child 4 sweets means to give each child 1 more .. since 5 more sweets is needed ie total of (30+5), then the number of children = (30 + 5)/1 = 35.

To make the child \"see\" .. start with small numbers - eg. Ms Lim wanted to give her students some sweets. If she were to give each student 3 sweets, she would have 8 left. If she were to give each student 5 sweets, she would be short of 4 sweets (ie need 4 more). How many students were there ?
For this one, start with each student already having the 3 sweets and Ms Lim has 8 sweets, so to give each student, she has to give 2 more to each but she would be short of 4 ie she need a total of (8+4)= 12 so that each student could have 2 more each.

So, number of students = 12/2 = 6

[starry15]

Mathizzzfun,

Thanks v much for the explanation and giving me the p3 link. Indeed V enlightening.

After reading and analyzing, I realized the method and logic is same as the Beef question as posted by rrjan above. Drawing a model out would visually enable the child to ‘see’ why we need to add 30 and 5. Will explain to my kid.

[MathIzzzFun]

starry15:

Mathizzzfun,

Thanks v much for the explanation and giving me the p3 link. Indeed V enlightening.

After reading and analyzing, I realized the method and logic is same as the Beef question as posted by rrjan above. Drawing a model out would visually enable the child to 'see' why we need to add 30 and 5. Will explain to my kid.

u r welcome.. this (was discussed in an earlier post) might help - http://www.flickr.com/photos/62167097@N02/5661546018/in/photostream

cheers.

[YumYum]

Hi,

Wld appreciate help on these Qns:

1. The ratio of the number of angelfish to the number of goldfish in tank A was 9:4. When 60 angelfish and 30% of the goldfish were transferred to tank B, the ratio of the no. Of angelfish to the no. Of goldfish in tank A became 15:7. How many fish were transferred from tank A to tank B?

Thanks

[Essential]

Hi math Guru, are u a math tutor. I am looking for a reliable tutor to help my DS. P6 next year