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    Tutor MathsGuru: Ask me for your burning Maths questions!

    Scheduled Pinned Locked Moved Primary Schools - Academic Support
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    • V Offline
      Vanilla Cake
      last edited by

      underthesea:
      Can someone help me with this maths question:


      There are 2 boxes. Box and Box Y, both of which contain pens and erasers only. The respective numbers of pens and erasers in Box X are in the ratio 1:3. The respective numbers of pens and erasers in Box Y are in the ratio 5:6. The number of items in Box X is thrice the number of items in Box Y.

      (a) Find the ratio of the number of pens in Box Y to the number of pens in Box X.
      (b) Knowing that there are 100 more erasers in Box Y than in Box X, find the number of erasers in Box Y.

      anything wrong with the question?TIA
      Sorry, underthesea. This is my view as I am also waiting for Mathsguru to provide solution to my Maths problem too.Where is this question from? There is a mistake in this question stating that there are 100 more erasers in Box Y than in Box X.

      I can only solve part (a) and let's wait for Mathsguru to solve part (b)

      (a)
      Box X
      P : E
      1 : 3
      33 : 99

      Box Y
      P : E
      5 : 6
      20 : 24

      Ratio: Total for Box X is 33+99=132 and Total for Box Y is 20+24=44
      132÷44=3
      fits the statement-\"The number of items in Box X is thrice the number of items in Box Y\".

      Ratio of the number of pens in Box Y to the number of pens in Box X is 20:33

      (b)
      From workings in part (a), the number of erasers in Box X is more than the number of erasers in Box Y. This contradicts the statement given in part (b) of the question ie \"Knowing that there are 100 more erasers in Box Y than in Box X.....\"

      Pls wait for Mathsguru to provide her solutions.

      1 Reply Last reply Reply Quote 0
      • CoffeeCatC Offline
        CoffeeCat
        last edited by

        underthesea:
        Can someone help me with this maths question:


        There are 2 boxes. Box and Box Y, both of which contain pens and erasers only. The respective numbers of pens and erasers in Box X are in the ratio 1:3. The respective numbers of pens and erasers in Box Y are in the ratio 5:6. The number of items in Box X is thrice the number of items in Box Y.

        (a) Find the ratio of the number of pens in Box Y to the number of pens in Box X.

        (b) Knowing that there are 100 more erasers in Box Y than in Box X, find the number of erasers in Box Y.

        anything wrong with the question?

        TIA
        yea i think sth's wrong too

        1 Reply Last reply Reply Quote 0
        • V Offline
          Vanilla Cake
          last edited by

          YLH88:
          Hi Mathsguru,

          Need your help with the below questions :

          1) Doran had 8/11 of the number of game cards Thomas had. After Thomas lost 18 cards to Doran, they both had the same number of cards.

          a) How many more game cards did Thomas have than Doran at first ?
          b) As the game continued, Doran won more cards from Thomas. How many more cards did Thomas lose to Doran such that Doran has 3 times as many cards as him ?

          I'm able to get the answer for (a), which is 36. But can't find for (b)
          Thank you!
          Hi YLH88,
          While waiting for Mathsguru's model solution, pls see whether mine using ratio is of any use or not?

          (a)
          D : T
          8 : 11
          16 : 22

          D : T
          19 : 19

          (16+22)÷2=19

          3u=18
          u=6
          6u=36

          At first, Thomas had 36 more game cards than Doran.

          (b)
          D : T
          19:19
          38: 38

          D : T
          3 : 1
          57:19

          6u=18 [from part (a) ie 6u=36, reduce half of 36 = 18 since 19:19 has been doubled to 38:38 in part (b)]
          u=3
          19u = 57
          Thomas lost 57 more cards to Doran.

          1 Reply Last reply Reply Quote 0
          • Y Offline
            YLH88
            last edited by

            [quote]Hi YLH88,

            While waiting for Mathsguru's model solution, pls see whether mine using ratio is of any use or not?

            (a)
            D : T
            8 : 11
            16 : 22

            D : T
            19 : 19

            (16+22)÷2=19

            3u=18
            u=6
            6u=36

            At first, Thomas had 36 more game cards than Doran.

            (b)
            D : T
            19:19
            38: 38

            D : T
            3 : 1
            57:19

            6u=18 [from part (a) ie 6u=36, reduce half of 36 = 18 since 19:19 has been doubled to 38:38 in part (b)]
            u=3
            19u = 57
            Thomas lost 57 more cards to Doran.[/quote]Hi Vanilla Cake,

            For (a), I got the answer using the model method. For the unit method, why did you change 8:11 to 16:22 ? Why do we multiple by 2 and not 3 or 4 etc ?

            For (b), why do you change from 19:19 to 38:38 and 3:1 to 57:19 ?

            Thank you!

            1 Reply Last reply Reply Quote 0
            • CoffeeCatC Offline
              CoffeeCat
              last edited by

              YLH88:
              [quote]Hi YLH88,

              While waiting for Mathsguru's model solution, pls see whether mine using ratio is of any use or not?

              (a)
              D : T
              8 : 11
              16 : 22

              D : T
              19 : 19

              (16+22)÷2=19

              3u=18
              u=6
              6u=36

              At first, Thomas had 36 more game cards than Doran.

              (b)
              D : T
              19:19
              38: 38

              D : T
              3 : 1
              57:19

              6u=18 [from part (a) ie 6u=36, reduce half of 36 = 18 since 19:19 has been doubled to 38:38 in part (b)]
              u=3
              19u = 57
              Thomas lost 57 more cards to Doran.
              Hi Vanilla Cake,

              For (a), I got the answer using the model method. For the unit method, why did you change 8:11 to 16:22 ? Why do we multiple by 2 and not 3 or 4 etc ?

              For (b), why do you change from 19:19 to 38:38 and 3:1 to 57:19 ?

              Thank you![/quote]Imagine ur drawing a model.
              8+11=19 is odd. do you want to draw 9 and a half units or just 38 units?

              1 Reply Last reply Reply Quote 0
              • D Offline
                Dharma
                last edited by

                YLH88:
                [quote]Hi YLH88,

                While waiting for Mathsguru's model solution, pls see whether mine using ratio is of any use or not?

                (a)
                D : T
                8 : 11
                16 : 22

                D : T
                19 : 19

                (16+22)÷2=19

                3u=18
                u=6
                6u=36

                At first, Thomas had 36 more game cards than Doran.

                (b)
                D : T
                19:19
                38: 38

                D : T
                3 : 1
                57:19

                6u=18 [from part (a) ie 6u=36, reduce half of 36 = 18 since 19:19 has been doubled to 38:38 in part (b)]
                u=3
                19u = 57
                Thomas lost 57 more cards to Doran.
                Hi Vanilla Cake,

                For (a), I got the answer using the model method. For the unit method, why did you change 8:11 to 16:22 ? Why do we multiple by 2 and not 3 or 4 etc ?

                For (b), why do you change from 19:19 to 38:38 and 3:1 to 57:19 ?

                Thank you![/quote](a)\tDoran : 8u + 18 = 11u – 18
                3u = 36 (Additional no. of cards Thomas had at first)

                (b)\tDoran had = 8u = 8 x 12 = 96
                Thomas had = 11u = 11 x 12 = 132

                96 + 1p = 3(132 – 1p)
                4p = 300
                1p = 75
                Additional cards Thomas lost = 75 – 18 = 57

                1 Reply Last reply Reply Quote 0
                • E Offline
                  Emelyn
                  last edited by

                  I have one question :


                  Mr Tay bought a massage chair for $888. He sold it to Mr Yeo for $850. He later bought the massage chair back from Mr Yeo for $900 and sold it to Mrs Tan for $1000. How much did Mr Tayy gain ?


                  MTIA !

                  1 Reply Last reply Reply Quote 0
                  • CoffeeCatC Offline
                    CoffeeCat
                    last edited by

                    Emelyn:
                    I have one question :


                    Mr Tay bought a massage chair for $888. He sold it to Mr Yeo for $850. He later bought the massage chair back from Mr Yeo for $900 and sold it to Mrs Tan for $1000. How much did Mr Tayy gain ?


                    MTIA !
                    do it step-by-step...
                    Or
                    when he buy, money is being gone from his pocket (so we will minus) and when he sell, money is being earned (so we will add).

                    -$888 + $850 -$900 + $1000
                    (if you are uncomfortable with a negative integer at the front then use the \"working backwards\" )

                    $1000 - $900 + $850 - $888 = $62

                    1 Reply Last reply Reply Quote 0
                    • E Offline
                      Emelyn
                      last edited by

                      CoffeeCat:
                      Emelyn:

                      I have one question :


                      Mr Tay bought a massage chair for $888. He sold it to Mr Yeo for $850. He later bought the massage chair back from Mr Yeo for $900 and sold it to Mrs Tan for $1000. How much did Mr Tayy gain ?


                      MTIA !

                      do it step-by-step...
                      Or
                      when he buy, money is being gone from his pocket (so we will minus) and when he sell, money is being earned (so we will add).

                      -$888 + $850 -$900 + $1000
                      (if you are uncomfortable with a negative integer at the front then use the \"working backwards\" )

                      $1000 - $900 + $850 - $888 = $62


                      The qn is actually from a colleague.
                      Her DD1 (P3) and DD2 (P2) teachers both said answer is $12.
                      I wonder why.....

                      1 Reply Last reply Reply Quote 0
                      • CoffeeCatC Offline
                        CoffeeCat
                        last edited by

                        lol you very free visiting the site during work =P.

                        Anyway this question has gotten the attention of 2 teachers? what’s their working?

                        1 Reply Last reply Reply Quote 0

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