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Friday, February 06, 2009

Tao Nan School P5 SA2 2007 Math Q48

There are some eggs in 3 baskets, A, B and C. 20% of the number of eggs in A is equal to 10% of the number eggs in B. The number of eggs in C is equal to 50% of the total number of eggs in A and B.

a) Express the number of eggs in C as a fraction of the number of eggs in B. (Leave your answer in its simplest form.)

b) If half of the eggs in B are taken out and placed into C, there will be 50 eggs in C. How many eggs are there in the 3 baskets?

Solution



a)
A + B ----- 15 units
C has 50% of 15 units ----- 15 units x 50/100 = 7.5 units

Fraction of number of eggs in C to B ----
7.5/10
= 75/100
= ¾ (Answer)

b)
If half of the eggs in B transferred to C -----
B ----- 10 units
Half of B ----- 5 units
C now will have, 7.5 units + 5 units ----- 12.5 units

12.5 units ----- 50 eggs
1 unit ----- 50 eggs divided by 12.5 = 4 eggs

Total number of eggs -----
A has 5 units
B has 10 units
C has 7.5 units
Total ----- 22.5 units

22.5 units ----- 22.5 x 4 = 90

Answer: There are 90 eggs in the 3 baskets.

20 comments:

  1. Can these problems be solved by Model Drawing ---

    Q1) In Hall A, 30% of the 800 people were men. In Hall B 40% of the 400 people were women and children. After some of the people in both hall had switched hall, 25% of the people in Hall A and 75% of those in hall B were men. How many people were there in Hall B after the change?

    Q2)During a warehouse book sale, Sally spent 62.5% of her money on 24 books and 18 pens. She also spent 25% of her remaining money on 18 files. Each pen costs 8/9 as much as the price of one book. The file costs $7.80 less than a book. Find the total cost of one book and one pen.

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  2. These problems can be easily solve using unit transfer method. I bought this book in this site:www.mathsheuristics.com

    ReplyDelete
  3. the first question can before and after concept: Totak unchanged

    the second question use proportion concept by unit methd

    ReplyDelete
  4. Hi anonymous 0251/0253

    Please show your full workings as it gives a chance for us to see your UTM method.

    Must show some samples as promotion lah, just like selling kuehs kuehs during festive seasons

    ReplyDelete
  5. i am not selling the book, i am nie trainee, attend the seminar before. But i think you can ask him in his blog.

    ReplyDelete
  6. Can this problem be solved by Model Drawing?

    Mr Lim spent $1496 on some comics and dictionaries altogether. The number of comics bought to the number of dictionaries bought was in the ratio of 3 : 2. A dictionary cost $4 more than a comic. The total cost of the comics was 20% more than the total cost of the dictionaries. Find the cost of a dictionary.

    ReplyDelete
  7. This can be solve by UTM under Proportion concept in less than 5 mins

    ReplyDelete
  8. Hi anon at 1033

    Please show, don't tell.
    Best Wishes

    ReplyDelete
  9. Hi anon @1033

    Could you tell us more about UTM? Is it a new revolutionary method to solve PSLE Maths? Is it more effective than Model Drawing? Will it enable students to see Maths just like the pictorial representation in MD? Is it within MOE syllabus?

    Could you show how UTM helps for the following questions?

    1) Peter started his journey from Town A to Town B. If he travelled at a speed of 80 km/h, he will arrive at Town B 1/3 hours late. If he travelled at a speed of 60 km/h, he will arrive at Town B 3/4 hours late.
    (a) Find the distance from Town A to Town B.
    (b) How long will he take to cover the journey with a speed of 90 km/h?

    2) A class of 40 pupils helped to carry bundles of old newspapers in an event organised to collect funds for the old folks. Each boy carried 3 stacks of newspapers and each girl carried 2 stacks. Altogether, the boys carried 30 more stacks than the girls. What is the ratio of the number of boys to number of girls in the class?

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  10. this was easy peasy!!!!

    ReplyDelete
  11. don't say like that

    ReplyDelete
  12. say,say,say yourself

    ReplyDelete
  13. how dare you say that to me???!!!

    ReplyDelete
  14. well you don't know who i am???my name is anonmynus.

    ReplyDelete
  15. i know you,you are creacidi shen.

    ReplyDelete
  16. how did you know??????!!!!!!!

    ReplyDelete
  17. it took me a minute to find that.i checked your idb blog of your account.to get there press start,click control panel.copy your subject and i'm done

    ReplyDelete
  18. hey it's arijit. i know him.in my school he had the highest psle aggregate score of 281 three years ago.

    ReplyDelete
  19. what is these utm about?

    ReplyDelete