Tutor MathsGuru: Ask me for your burning Maths questions!

[maggilim]

Hi all , i am very worried as my girl is in P5 and she seems to be veri \"slow\" in her maths. She had been to popular Tution center but still see no improvement. Any suggestions?

[ADoc]

maggilim:

Hi all , i am very worried as my girl is in P5 and she seems to be veri \"slow\" in her maths. She had been to popular Tution center but still see no improvement. Any suggestions?

Hi there! Since we don't know much about your kid, here're a number of generalisations for so-called slow-learners. No offence intended pls. You may wanna run thru these questions (non-exhaustive) before deciding your course of action. Pls know that these questions have nothing to do with intelligence at all. My nephew is a \"slow learner\". With these questions and the help of a doc, we concluded he has no learning disability whatsoever, other than the one incident whereby he was put down by his friends for not being able to answer a \"simple\" math question. He lost all confidence and didn't dare to even pen his workings until he \"confirmed\" his approach with an adult / teacher. It was quite a painful process and he needed lots of praise and positive reinforcements before he regained his confidence. phew!

1. does she have problems with other subjects such as english?
2. does she have a hearing or visual disability that you are not aware of?
3. does she have difficulty recognising numbers, especially those look-a-likes, i.e. 9 & 6, 1000, 100000?
4. does she have difficulty recognising \"obvious\" patterns of numbers and/or shades?
5. has she been ridiculed before in class by her mates or even math teachers?
6. is she an exceptionally shy person?
7. is she afraid to try working out the answers?
8. does she have any problem reciting 1-12 multiplication table?
9. is she an audio or visual person?
10. can she tell the difference between a very large number and a very small number?

cheers!

[iFruit]

pixiedust:

Thank you iFruit. You made it look so simple !

The solution is considered algebra method ?

Welcome pixiedust...in my books it IS algebra..

Regards.

[Muffins]

ADoc:

Muffins:

...

Total number of members who did not take part in the competition: 5ϰ + 12

Boys who did not take part: 3ϰ

(5ϰ+12) - 3ϰ = 2ϰ + 12

6 X 3 = 18

6 X 5 = 30

30 + 12 = 42

18/42 = 3/7

Hmm.... My working seems correct. However, you guys' answers are 3/10 though... any ideas or advice?

P.S.
Total number of boys in club = 24
Total number of girls in club = 36

Hi there! Your answer is using \"no. of club members who did not take part in the competition\" as the denominator, whereas previous answer/s used \"total club members\" = 60.
Oh well...as with my previous post, I'm of the opinion that the denominator should be \"no. of club members who did not take part in the competition\" too.

cheers!


hi members, these are just for fun: what do these statements mean to you?

[1] The fraction of boys who did not take part in the competition is...
[2] Of those who did not take part in the competition, the fraction of boys is...

[3] I love you only
[4] Only I love you
[5] I only love you
[6] I love only you

But didn't the question ask for that????

Am still not sure whether i am correct... :faint:

[Bunny27]

Hi, pls help me with these questions:


1. Luke and Isaac had $95 at first. After they each spent an equal amount of money, Luke had four times as much money as Isaac. How much money did each of them spend?

2. The ratio of the number of red marbles to the number of blue marbles on a box was 7:4. When 10 red marbles were replaced by 10 blue marbles, the ratio of the number of red marbles to the number of blue marbles became 1:2. How many red marbles were there at first?

3. The ratio of John’s age to Ryan’s age is 3:1 now. 25 years later, the ratio will become 4:3. How old is John now?

4. The ratio of the number of 20-cent coins to the number of 50-cent coins to the number of $1 coins in a bag is 2:6:7. If the total amount if money in the bag is $156, how many coins are there altogether?

Thanks

[Bunny27]

Hi, pls help me with these questions:


Hi, pls help me with these questions:

1. Luke and Isaac had $95 at first. After they each spent an equal amount of money, Luke had four times as much money as Isaac. How much money did each of them spend?

2. The ratio of the number of red marbles to the number of blue marbles on a box was 7:4. When 10 red marbles were replaced by 10 blue marbles, the ratio of the number of red marbles to the number of blue marbles became 1:2. How many red marbles were there at first?

3. The ratio of John's age to Ryan's age is 3:1 now. 25 years later, the ratio will become 4:3. How old is John now?

4. The ratio of the number of 20-cent coins to the number of 50-cent coins to the number of $1 coins in a bag is 2:6:7. If the total amount if money in the bag is $156, how many coins are there altogether?

Thanks

:welcome:

Dear Parents,

Are you frustrated/stuck when helping your child solve his/her Maths questions? Are you inclined to use Algebra most of the time? Do you have difficulty trying to use diagrams or other heuristic methods (that Primary School students learn) to solve?

:idea: Post your questions here and see how MathsGuru solve them to the best of her ability. Detailed solutions will be posted back in this thread.

So start asking and watch this space!!

Cheers :celebrate: ,
MathsGuru

P/S (Disclaimer, in case you're wondering...):
Although MathsGuru is a full-time Maths tutor, this thread is meant to be an absolutely free resource for parents (or even children) with no strings attached. Just someone who's passionate about Maths and wanna spread the fun in learning Maths with others. :D[/quote]

[Bunny27]

Hi MathsGuru,

Need help for these Questions:

A) There were 1072 pupils in a school hall.
5/8 of them were girls. When some of the girls left the hall, the number of girls who stayed behind made 7/13 of the total number of pupils who remained in the hall.
How many girls left the hall?

B)There were some 20cents coins in Drawer A and some 50cents coins in Drawer B. The amount of money in Drawer B was $28.90 more than the amount in Drawer A. There were 46 more coins in Drawer A than in Drawer B. Find the amount of money in Drawer A.

Thanks alot.

:welcome:

Dear Parents,

Are you frustrated/stuck when helping your child solve his/her Maths questions? Are you inclined to use Algebra most of the time? Do you have difficulty trying to use diagrams or other heuristic methods (that Primary School students learn) to solve?

:idea: Post your questions here and see how MathsGuru solve them to the best of her ability. Detailed solutions will be posted back in this thread.

So start asking and watch this space!!

Cheers :celebrate: ,
MathsGuru

P/S (Disclaimer, in case you're wondering...):
Although MathsGuru is a full-time Maths tutor, this thread is meant to be an absolutely free resource for parents (or even children) with no strings attached. Just someone who's passionate about Maths and wanna spread the fun in learning Maths with others. :D[/quote]

[ADoc]

Bunny27:

Hi, pls help me with these questions:


Hi, pls help me with these questions:

1. Luke and Isaac had $95 at first. After they each spent an equal amount of money, Luke had four times as much money as Isaac. How much money did each of them spend?

2. The ratio of the number of red marbles to the number of blue marbles on a box was 7:4. When 10 red marbles were replaced by 10 blue marbles, the ratio of the number of red marbles to the number of blue marbles became 1:2. How many red marbles were there at first?

3. The ratio of John's age to Ryan's age is 3:1 now. 25 years later, the ratio will become 4:3. How old is John now?

4. The ratio of the number of 20-cent coins to the number of 50-cent coins to the number of $1 coins in a bag is 2:6:7. If the total amount if money in the bag is $156, how many coins are there altogether?

Hi there! Hope these answers are helpful. Didn't have the time to do up a pretty model for better visualisation. By the way, your Q1 could be wrongly worded (or have missing parts) as there are literally infinite number of solutions based on your question. (you will understand the rationale when you get to Upper Sec )

Q2.
before
RED : BLUE = 7 : 4

after
RED : BLUE = 1 : 2

Key Concept: total number of (ratio) units must remain the same since there is NO net change in total number of Blue & Red marbles (just a mere exchange)

How to make the (ratio) units before and after the same?
Total number of (ratio) units before = 7 + 4 = 11
Total number of (ratio) units after = 3

The (lowest) common multiple = 3 x 11 = 33

before
RED : BLUE = 7 : 4 = 21 : 12 (x 3)

after
RED : BLUE = 1 : 2 = 11 : 22 (x 11)

Ans = 21 red marbles
------------------------------------------------------------------------------------------------------------

Q3.
now
John : Ryan = 3 : 1

after 25 yrs
John : Ryan = 4 : 3

Key Concept: the difference between the (ratio) units of each person (object) remains unchanged after an equal amount is added to both persons (objects) (this is a typical \"aging\" question whereby everyone of us will age by an equal amount of time (days, months, years) unless one of us is from another planet)

Difference in (ratio) units of John's & Ryan's age = 3-1 = 2

Difference in (ratio) units of John's & Ryan's age in 25 yrs' time must be 2 as well, but 4-3 =1.
We need to multiply the ratio by 2 to give 8 : 6

increase in number of units for both persons = 5U (8 - 3 = 5; 6 - 1 = 5)
so 5U = 25 yrs --> 1U = 5yrs

Ans = 3U x 5 = 15 yrs' old
------------------------------------------------------------------------------------------------------------

Q4.
ratio of the number of 20cent, 50cent, & $1 coins = 2 : 6 : 7

ratio of the worth of 20cent, 50cent, & $1 coins = 2x20 : 6x50 : 7x100 = 40 : 300 : 700 = 2 : 15 : 35
this means that for every 2 units worth of 20c coins, there are 15 units worth of 50c coins, & 35 units worth of $1 coins

Key Concept: need to distinguish between number of coins (or dollar notes) and their worth in dollars & cents, & convert them into their respective ratios

total number of units (in terms of worth) = 2 + 15 + 35 = 52U = $156

so 1U = 156 / 52 = $3
amount of 20c = $3 x 2 = $6 --> number of 20c coins = 600c / 20c = 30
amount of 50c = $3 x 15 = $45 --> number of 50c coins = 4500c / 50c = 90
amount of $1 = $3 x 35 = $105 --> number of 20c coins = $105 / $1 = 105 [check 30 : 90 : 105 = 6 : 18 : 21 = 2 : 6 : 7]

Ans = 30 + 90 + 105 = 225 coins

[fxchow]

Hi,


Can anyone help in this question. (Nah Hua CA1 2011 , Q12)

Jan and Kay had equal number of sweets and equal number of chocolates.
Jan ate 12 sweets and Kay ate 18 chocolates and then the ratio of Jan's sweets to chocolates became 1:7 and the ratio of Kay's sweets to chocolates became 1:4.
How many sweets did Jan have at first?

TIA

[ADoc]

Bunny27:

Hi MathsGuru,

Need help for these Questions:

A) There were 1072 pupils in a school hall.
5/8 of them were girls. When some of the girls left the hall, the number of girls who stayed behind made 7/13 of the total number of pupils who remained in the hall.
How many girls left the hall?

B)There were some 20cents coins in Drawer A and some 50cents coins in Drawer B. The amount of money in Drawer B was $28.90 more than the amount in Drawer A. There were 46 more coins in Drawer A than in Drawer B. Find the amount of money in Drawer A.

Hi again!

pls see image file.
For A), I have included two variations (model & ratio). For the ratio method, since there is no change in the number of boys, we must change the ratio units of boys \"before\" to 6 in order to maintain the same number of units of boys \"before\" & \"after\". [note!! without this step, we cannot equate each unit \"before\" & \"after\" to be of the same value]

cheers!

http://postimage.org/image/w1qwaokk/

http://postimage.org/image/w1sju12c/