Tutor MathsGuru: Ask me for your burning Maths questions!

[Yu Xuan]

lymmlim:

Hi,


DS P6 revision question, please help.

A company has a total of 2840 local and foreign employees. 0.4 of the male employees and 0.25 of the female employees are foreigners. There are 1857 local employees in all. Find the number of foreign male employees

Thanks.

Hi

M --> units of Male
F --> units of Female

Male Local : Male Foreign = 3 : 2
Female Local : Female Foreign = 3 : 1

5 M + 4 F --> 2840
3 M + 3F --> 1857

15M + 12F --> 8520
15M + 15F --> 9285
Comparing both,
3F --> 765
Total Female --> 765 /3 * 4 =1020

Total Male --> 2840 - 1020 = 1820
Male Foreign --> 1820 / 5 * 2 = 728

[jeffreythp.030074yahoo.030074com.030074sg]

Hi,


Need solution for this question:

1. Tanks X and Y are each filled with some water. If water from Tank Y is poured into Tank X until the water in Tank X reaches the brim, there will be
8 litres of water left in Tank Y. If water from Tank X is poured into Tank Y until the water in Tank Y reaches the brim, there will be 26litres of water left in Tank X. The ratio of the volume of Tank X to the volume of Tank Y is 5:3. How many more litres of water are needed to fill both tanks to their brim?

TIA

: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]

[Yu Xuan]

A1:

Hi,


1. A florist had a total of 272 roses and lilies in the ration 12:5. After selling away twice as many roses as lilies, the ratio of the number of roses to the number of lilies was then 5:2. How many roses did she sell?

Roses --> 272 / 17 * 12 = 192
Lilies --> 272 / 17 * 5 = 80

Rose
5 parts --> 192 - 2 units
10 parts --> 384 - 4 units

Lillies
2 parts --> 80 - 1 unit
10 parts --> 400 - 5 units

384 - 4 units = 400 - 5 units (you can draw a model using this]
1 unit --> 16
2 units --.16 * 2 = 32

[Yu Xuan]

A1:

Hi,



1. Tanks X and Y are each filled with some water. If water from Tank Y is poured into Tank X until the water in Tank X reaches the brim, there will be
8 litres of water left in Tank Y. If water from Tank X is poured into Tank Y until the water in Tank Y reaches the brim, there will be 26litres of water left in Tank X. The ratio of the volume of Tank X to the volume of Tank Y is 5:3. How many more litres of water are needed to fill both tanks to their brim?

Difference in volume --> 5u -3u = 2u

There is some existing water in both tanks. The total volume of the existing water remains the same whether it is poured into Tank X or Y. Hence the 'excess' water is the difference in the volume of the two tanks. i.e.
2u --> 26 - 8 = 18
1u --> 9
Volum of Tank X --> 9 * 5 = 45
Volume of Tank Y --> 9 * 3 = 27

To find the existing volume of water in both tanks, we simply add the 8 litres of water to the volume of X ;
45 + 8 = 53

So the amount of water required to fill up both tanks is
45 + 27 - 53 = 19 litres

[ADoc]

A1:

Hi,


Can someone help with these questions:

3. Tanks X and Y are each filled with some water. If water from Tank Y is poured into Tank X until the water in Tank X reaches the brim, there will be 8 litres of water left in Tank Y. If water from Tank X is poured into Tank Y until the water in Tank Y reaches the brim, there will be 26litres of water left in Tank X. The ratio of the volume of Tank X to the volume of Tank Y is 5:3. How many more litres of water are needed to fill both tanks to their brim?

4. Dolly had 80 more stickers than Jenny. Dolly gave 25% of her stickers to Jenny. Jenny in return gave 60% of her stickers to Dolly. In the end, Dolly had 100 stickers more than Jenny. How many stickers did Dolly have at first?

Hi, forgot attachment for Q3. There's really no need for the model if you're familiar with the \"internal transfer\" concept.

Method for Q4 (ans: 116) is the same as Q2 (ASSUMING that \"in return\" means 60% of whatever Jenny had after receiving 25% from Dolly). Do note that if you wish to use the net-change method, the \"net increase\" of 100-80 = 20, must be divided by two, i.e. each of us has 10 marbles, I give you 1 marble (net change of 1 for both of us), but the resulting difference between our marbles is 11 - 9 = 2 (twice). [important to understand this!]

You can also use the total amount method as illustrated in Q3 since Q4 is similar to \"internal transfer\" but... Try it out to see what I mean by \"but...\"

cheers!
http://postimage.org/image/1fc4cdcro/

[jeffreythp.030074yahoo.030074com.030074sg]

Thanks ADoc for ur kind assistant in all these questions. I will try to figure it out again

ADoc:

A1:

Hi,

Can someone help with these questions:

3. Tanks X and Y are each filled with some water. If water from Tank Y is poured into Tank X until the water in Tank X reaches the brim, there will be 8 litres of water left in Tank Y. If water from Tank X is poured into Tank Y until the water in Tank Y reaches the brim, there will be 26litres of water left in Tank X. The ratio of the volume of Tank X to the volume of Tank Y is 5:3. How many more litres of water are needed to fill both tanks to their brim?

4. Dolly had 80 more stickers than Jenny. Dolly gave 25% of her stickers to Jenny. Jenny in return gave 60% of her stickers to Dolly. In the end, Dolly had 100 stickers more than Jenny. How many stickers did Dolly have at first?

Hi, forgot attachment for Q3. There's really no need for the model if you're familiar with the \"internal transfer\" concept.

Method for Q4 (ans: 116) is the same as Q2 (ASSUMING that \"in return\" means 60% of whatever Jenny had after receiving 25% from Dolly). Do note that if you wish to use the net-change method, the \"net increase\" of 100-80 = 20, must be divided by two, i.e. each of us has 10 marbles, I give you 1 marble (net change of 1 for both of us), but the resulting difference between our marbles is 11 - 9 = 2 (twice). [important to understand this!]

You can also use the total amount method as illustrated in Q3 since Q4 is similar to \"internal transfer\" but... Try it out to see what I mean by \"but...\"

cheers!
http://postimage.org/image/1fc4cdcro/

[ADoc]

Hi A1! You’re most welcome!

I hope I didn’t confuse you further with my solutions.

[anneshirleygilbert]

ADoc:

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

Hi there! The steps may be simple but this question is slightly \"trickier\" in the sense that students must be able to manage and equate 2 different types of units. I hope I have presented the solution in the most easy-to-understand manner by using K (Kay) & J (Jay) instead of the usual U (Units). We can also use the ratio method but I feel it may be rather complex, hence I have not included this variation of the solution. Hope this is useful to you.

cheers!

http://postimage.org/image/ycxyk6w4/

Hello ADoc,
I couldn't view your image when I clicked it. Any idea what I didn't do right? The question is very interesting .. I don't want to skip it.

[ADoc]

anneshirleygilbert:

Hello ADoc,
I couldn't view your image when I clicked it. Any idea what I didn't do right? The question is very interesting .. I don't want to skip it.

hi there! You can try this link:
http://postimage.org/image/ycxyk6w4/

[Bunny27]

Hi,


Can you help of solve this question?
In the 1st week of a fund raising campaign, class 6a raised 4 times as much as class 6b. In the 2nd week, 6a raised another $240 while 6b raised another $160. Given that 6a raised thrice as much as 6b within these 2 weeks, what was the total amount of money raised by the 2 classes?

Thanks!

mathsguru:

Original Title: Let MathsGuru Answer Your Burning Maths Questions!

: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.