Friday, October 16, 2009

Cookies Question - PSLE Maths 2009

Question (Cookies)

Sally baked some cookies to sell.

3/4 of them were chocolate cookies and the remaining were almond cookies.
After she sold 5/6 of chocolate cookies and 210 almond cookies, she had 1/5 of the cookies left.

How many cookies did she sell?


Solution :

Coming Soon ....

Give it a try ....

3 comments:

  1. if you use algebra.

    let x be the total number of cookies, so you want to find 4/5 x as your answer.

    based on the question

    x - (5/6)*(3/4)x - 210 = (1/5)x

    when solved for x gives you x=1200

    then (4/5)x = (4/5)*1200 = 960

    I think most of the questions posted so far are not actually hard. they are just conceptually very complicated to visualise before solving, which is a problem for P6 kids because they can be very abstract and if you accept Piaget's theory of cognitive development, many kids at 12 would not have gone past the concrete operational stage and still lack the cognitive skills to visualize such things.

    I think its most obvious in the time question. I can bet a whole lot of adults are not able to solve that question

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  2. My method > Convert all fractions to equivalent ratios.

    I chose 100.
    20u > Left
    minus the Chocolates left and you get 7.5
    7.5 u > 210

    1u>210/7.5 = 28

    Total Sold > 80u > 28x80 = 2240

    I do not even know the answer , Im 12, But GOOD... I got the curry puff question correct.

    I got 77 marks for math and i highly doubt my answer.

    ReplyDelete
  3. 5/6 = 5/8 as a whole using model solving approach
    5/8 = 25/40
    1/5 = 8/40
    40/40 - 25/40 - 8/40 = 7/40
    7 units = 210
    25 units = 750
    750 + 210 = 960 ( Total cookies sold )

    Joleen Tutor

    ReplyDelete