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Tuesday, December 11, 2007

Anglo-Chinese School (Primary) P5 SA2 2006 Math Question (Q37)

The ratio of the number of 20-cent coins to the number of 50-cent coins to the number of $1 coins in a bag is 2 : 4 : 7. Given that the total amount of money in the bag is $47, how many coins are there altogether?

Solution



47 units ----- $47 (Total amount of money in bag is $47)

1 unit ----- $47 divided by 47 = $1

Value of 20-cent coins ----- 2 units ----- $2
Value of 50-cent coins ----- 10 units ----- $10
Value of $1 coins ----- 35 units ----- $35

No. of 20-cent coins ----- $2 divided by 20 cents ----- 10 coins
No. of 50-cent coins ----- $10 divided by 50 cents ----- 20 coins
No. of $1 coins ----- $35 divided by $1 ----- 35 coins


Total number of coins in bag

10 + 20 + 35 = 65

Answer: There were 65 coins in the bag.
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2 comments:

  1. Anonymous14 April 2008 at 10:12 pm

    isn't it faster to do this:

    Ratio 20 cents: 50 cents : $1
    = 2 : 4 : 7
    2 x 20 cents + 4 x 50 cents + 7X 100 cents = 940 cents

    4700 / 940 = 5 groups

    5 x (2 + 4 + 7) = 65 coins

    ReplyDelete
  2. Excel Eduservice15 April 2008 at 9:59 am

    Dear Anonymous,

    My reply can be found here.

    ReplyDelete