Q&A - P3 Math

[Michaelia0816]

kwcllf:

jwxh:

Please help me to solve this problem


A skirt and a dress cost $155.
A skirt and a pair of pants cost $95
A skirt, a dress and a pair of pants cost $300
How much does a skirt cost?
Thank You!

From the info, a pair of pants cost $145 (300 - 155)
How can a skirt and a pair of pants cost $95?

Seems like there are errors in the info.

Yup, I also think there was a mistake in it, I think it would be better to change it to:

A skirt and a dress cost $155
A skirt and a pair of pants cost $145.
A shirt, a dress and a pair of pants cost $300.
How much does a skirt cost?

How much did the cost of the dress than a pair of pants---$155-$145=$10
Possible answer (skirt) ---- any answer between $15 to $140.

[Michaelia0816]

Not so reasonable, do I, but no matter how I minus, the differences is always $10! Do everyone agrees with me?

[AgonyMum]

Are there any Math teachers/ experts who can help explain these 4 questions to me? I have asked another resident expert and I am still not "catching" it.

Please help! Thanks very much in advance! Please provide detailed explanation as my child and I are both new to this topic of "Working Backwards".

1. A went to the bank to withdraw some money. He withdrew half of his savings and $5 more for the first time, and half of the remaining savings and $10 more for the second time. The amount of savings left was $125. What was his original amount of savings?

2. A was repairing the road. He repaired 160m less than half the length of the road on the first day. On the second day, he repaired 60m less than half the remaining road. The third day, he repaired half the remaining road and 30m more. What was left after the third day was 140m. What was the total length of the road?

3.A owned a gigantic bookshelf stuffed with books.It had 3 sections,the bottom section, the middle section and the top section. There were a total of 192 books on the shelf. From the top section, A transferred to the middle section the number of books the middle section originally had. Then, from the middle section,he transferred to the bottom section the number of books the bottom section had originally. Lastly, from the bottom section, he transferred to the top section the number of books that the top section contained after the first transfer. Now, the number of books in all 3 sections are equal. How many books were there in the top, middle and bottom section respectively at the very beginning?

4. A, B and C owned 240 books altogether. D took from A the number of books that was equal to what B had, and gave them to B. Then D took from B a number of books that was equal to what C had, and gave them to C. Lastly, D took from C a number of books that was equal to what A had left after the first transfer, and gave them to A. After this,the number of C’s books were thrice of A’s while the number of B’s books were twice of A’s. How many books did A,B and C have at the very beginning?

[MathIzzzFun]

AgonyMum:

Are there any Math teachers/ experts who can help explain these 4 questions to me? I have asked another resident expert and I am still not \"catching\" it.

Please help! Thanks very much in advance! Please provide detailed explanation as my child and I are both new to this topic of \"Working Backwards\".

1. A went to the bank to withdraw some money. He withdrew half of his savings and $5 more for the first time, and half of the remaining savings and $10 more for the second time. The amount of savings left was $125. What was his original amount of savings?

2. A was repairing the road. He repaired 160m less than half the length of the road on the first day. On the second day, he repaired 60m less than half the remaining road. The third day, he repaired half the remaining road and 30m more. What was left after the third day was 140m. What was the total length of the road?

3.A owned a gigantic bookshelf stuffed with books.It had 3 sections,the bottom section, the middle section and the top section. There were a total of 192 books on the shelf. From the top section, A transferred to the middle section the number of books the middle section originally had. Then, from the middle section,he transferred to the bottom section the number of books the bottom section had originally. Lastly, from the bottom section, he transferred to the top section the number of books that the top section contained after the first transfer. Now, the number of books in all 3 sections are equal. How many books were there in the top, middle and bottom section respectively at the very beginning?

4. A, B and C owned 240 books altogether. D took from A the number of books that was equal to what B had, and gave them to B. Then D took from B a number of books that was equal to what C had, and gave them to C. Lastly, D took from C a number of books that was equal to what A had left after the first transfer, and gave them to A. After this,the number of C's books were thrice of A's while the number of B's books were twice of A's. How many books did A,B and C have at the very beginning?

Hi

Q1 ..

http://i44.tinypic.com/nzg67s.png\">

busy at moment, will the rest of the questions for the other experts..

cheers.

[MathIzzzFun]

AgonyMum:

Are there any Math teachers/ experts who can help explain these 4 questions to me? I have asked another resident expert and I am still not \"catching\" it.

Please help! Thanks very much in advance! Please provide detailed explanation as my child and I are both new to this topic of \"Working Backwards\".


2. A was repairing the road. He repaired 160m less than half the length of the road on the first day. On the second day, he repaired 60m less than half the remaining road. The third day, he repaired half the remaining road and 30m more. What was left after the third day was 140m. What was the total length of the road?

Hi

Q2.

http://www.flickr.com/photos/62167097@N02/7108225881/in/photostream

cheers.

[Always21]

Hi,

These problem sums are for P3 or higher Pri?

[blushes]

Hi all


have a question, i need help in solving.

A book cost $4 and a pen cost $3. Mr Ng spent $ 252 on equal number of book and pen. Find out how many pen was purchased?

thanks

[mrswongtuition]

blushes:

Hi all


have a question, i need help in solving.

A book cost $4 and a pen cost $3. Mr Ng spent $ 252 on equal number of book and pen. Find out how many pen was purchased?

thanks

Since he bought equal numbers of books and pens, there will be a certain number of SETS of a book and a pen.
Each set costs $4 + $3 = $7
$252 divide $7 = 36 sets

Since there's 1 pen in each set, he bought 36 pens.

[blushes]

Thanks!!

oh…its so easy…kept thinking it not so simple.

[AgonyMum]

Yes,I finally understood your solution for Qn 2!!

Thanks SO MUCH, MathIzzzFun
Could you kindly present the workings for the other 3 questions in the same \"form\"? I think I can only comprehend that particular kind of model.I am not too good visually. I really could not understand the other \"drawing\". So sorry to trouble you and many, many thanks in advance!!
Hi Always21, these questions were given out to my child who is in P3. They were just supposed to look through and those who are smart will be able to solve them,I guess. Unfortunately, both my child and I did not even know how to start solving the questions. According to MathIzzzFun, these questions could be pitched to children in any level cos once they know the concept well, they can solve them. What is to become of my child,I wonder?? Thank Goodness for helpful souls like MathIzzzFun. He really helped mychild and I previously too.