Friday, October 16, 2009

Ballon Question - PSLE Maths 2009

Question (Balloons)

String of 2 big balloons is 90cm.,
String of 5 small balloons is 1.2m.,

If both strings are of the same length, there would be 105 more small balloons than the big balloons.

How many balloons are there altogether?


Solution

Coming soon ....


2 comments:

  1. The first step is to find the LCM of 90 and 120 to get the common length that the two sizes of balloons can have.

    Therefore, LCM = 360. (Have omitted the steps to get that)

    Therefore, the Big balloon string which has a length of 90 cm would need 4 sets of such to get 360 cm, giving a total of 4 x 2 = 8 balloons.

    the Small balloon string which has a length of 120 cm would need 3 sets of such to get 360 cm, giving a total of 3 x 5 = 15 balloons.

    Since there are 105 small balloons as compared to big balloons, we have to see how many sets of 15 small balloons and 8 huge balloons are there to get this situation:
    105/ (15-8) = 15 sets

    Hence total number of balloons = 15 x 8 + 15 x 15 = 345 balloons

    ReplyDelete
  2. Same Answer Different Method.

    Find the length of 1 big ballon ( 90/2 = 45)
    Small Ballon > (120-5=24)
    Find how much more you can fit into the space that is more.

    24 x 105 =2520

    Next , find the difference between the Big and Small Ballons.

    Divide the Gap you can fit into to find the normal amount.This method is very similar to assumption.

    I just tweaked the way of doing so.

    SO as you can see the answer of 2520/Dif(21) = 120

    120+(120-105)= 120+5 = 125 . Tadaa ~

    WRONG!

    Check it : 120 x 24 =2880
    5x45 = 225
    Try ! The numbers DO NOT TALLY !

    How about we add the actual plus more small balloons...

    120+105+120 = 345!

    Check it ! It is right!

    Im an 12 year old at April now , on an normal school.

    DO pose more harder questions,it poses a challenge fore me! HAHAHAHAHAHAHAHA!

    ReplyDelete