Tutor MathsGuru: Ask me for your burning Maths questions!

[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/

[chrisu]

Hi I’ve a question from my P6 girl;


3 men, A, B and C, worked together to paint a wall. If the painting was done by one man, the time taken to complete the wall for A, B and C would have been 6 hours, 8 hours and 12 hours respectively. A and B had painted for 3 hours after which A rested. B and C then continued with the painting. What would be the total number of hours taken to complete the wall? (Give your answer as a mixed number).

The given answer by the teacher is 3 and 3/5 hours but my answer is 3 and 3/7 hours. Pls help best with workings. Thanks.

[fxchow]

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/

Hi ADoc,
Thank you very much!
:lovesite:

[ADoc]

chrisu:

Hi I've a question from my P6 girl;


3 men, A, B and C, worked together to paint a wall. If the painting was done by one man, the time taken to complete the wall for A, B and C would have been 6 hours, 8 hours and 12 hours respectively. A and B had painted for 3 hours after which A rested. B and C then continued with the painting. What would be the total number of hours taken to complete the wall? (Give your answer as a mixed number).

The given answer by the teacher is 3 and 3/5 hours but my answer is 3 and 3/7 hours. Pls help best with workings. Thanks.

Hi there! Here's my solution. You can advise your kid to think of this sort of problem as the distance - speed - time problem.

- amount of wall to be completed ~ distance
- completion per hour ~ speed (just like km per hour)

hope it's useful!
cheers!

fraction of wall completed for every hour of work
A -> 1/6, B -> 1/8, C -> 1/12 (eg. A takes 6 hours to complete one wall on his own. In other words, A will complete 1/6 of one wall per hour... ~ \"speed\" or \"rate of completion\")

A & B worked for 3hours
A would have completed 3 x (1/6) = 1/2 of the wall
within the same 3hours, B would have completed 3 x (1/8) = 3/8 of the wall

Total fraction of the wall completed in 3 hours by A & B = (1/2) + (3/8) = 7/8

Amount left uncompleted = 1 - (7/8) = 1/8 of the wall

with B & C
every hour, they would complete (1/8) + (1/12) = (3/24) + (2/24) = 5/24 of the wall

therefore time taken to complete the 1/8 of the wall = (1/8) / (5/24) = (1/8) x (24/5) = 3/5hr [D-S-T: to get T -> D/S]

ans: total time required = 3hr + 3/5hr = 3 & 3/5 hr

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

Hi,


Can someone help with these questions:

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?

2. Julian had 300 more cards than Faizal. Julian gave 3/5 of his cards to Faizal. Faizal then gave 1/4 of the total number of what he had then to Julian. In the end, Faizal had 300 more cards than Julian. How many cards did Julian have at first?

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?
: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]

A1:

Hi,


Can someone help with these questions:

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?

2. Julian had 300 more cards than Faizal. Julian gave 3/5 of his cards to Faizal. Faizal then gave 1/4 of the total number of what he had then to Julian. In the end, Faizal had 300 more cards than Julian. How many cards did Julian have at first?

Hi there, pls see solutions. cheers!

http://postimage.org/image/1fau1bmxw/
http://postimage.org/image/1fiqhrbvo/

[rossypolly]

Justin baked some pies. 1/3 of the pies were chicken pies & the rest were vegetable pies. He packed 3/4 of the vegetable pies into big boxes & the rest of the vegetable pies into small boxes. each big box of vegetable pies made up 1/12 of the total no. of pies. Each small box of vegetable pies made up 1/16 of the total no of pies.


How many big boxes of vegetable pies were there?

How many small boxes of vegetable pies were there?

[chrisu]

Thank you very much. Now this is really an easy way to remember the method.

ADoc:

chrisu:

Hi I've a question from my P6 girl;

3 men, A, B and C, worked together to paint a wall. If the painting was done by one man, the time taken to complete the wall for A, B and C would have been 6 hours, 8 hours and 12 hours respectively. A and B had painted for 3 hours after which A rested. B and C then continued with the painting. What would be the total number of hours taken to complete the wall? (Give your answer as a mixed number).

The given answer by the teacher is 3 and 3/5 hours but my answer is 3 and 3/7 hours. Pls help best with workings. Thanks.

Hi there! Here's my solution. You can advise your kid to think of this sort of problem as the distance - speed - time problem.

- amount of wall to be completed ~ distance
- completion per hour ~ speed (just like km per hour)

hope it's useful!
cheers!

fraction of wall completed for every hour of work
A -> 1/6, B -> 1/8, C -> 1/12 (eg. A takes 6 hours to complete one wall on his own. In other words, A will complete 1/6 of one wall per hour... ~ \"speed\" or \"rate of completion\")

A & B worked for 3hours
A would have completed 3 x (1/6) = 1/2 of the wall
within the same 3hours, B would have completed 3 x (1/8) = 3/8 of the wall

Total fraction of the wall completed in 3 hours by A & B = (1/2) + (3/8) = 7/8

Amount left uncompleted = 1 - (7/8) = 1/8 of the wall

with B & C
every hour, they would complete (1/8) + (1/12) = (3/24) + (2/24) = 5/24 of the wall

therefore time taken to complete the 1/8 of the wall = (1/8) / (5/24) = (1/8) x (24/5) = 3/5hr [D-S-T: to get T -> D/S]

ans: total time required = 3hr + 3/5hr = 3 & 3/5 hr

[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.

[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