Q&A - P5 Math

[KSP]

you can post your maths Q here


P3 http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=66&t=149&p=749385#p749385
P4 http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=67&t=25121&start=560
P5 http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=68&t=25129&start=700
P6 http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&start=5730

There are many experts can help.

[wenray]

how do u solve this?


Bin and Wei had some specimens of a butterfly. The ratio of the number of Bin’s specimens to the number of Wei’s specimens was 3:8. After Wei gave 8 specimens to Bin, he still had twice as many specimens as Bin. How many specimens did Bin have at first?

Thanks!

[MathIzzzFun]

wenray:

how do u solve this?


Bin and Wei had some specimens of a butterfly. The ratio of the number of Bin's specimens to the number of Wei's specimens was 3:8. After Wei gave 8 specimens to Bin, he still had twice as many specimens as Bin. How many specimens did Bin have at first?

Thanks!

Hi

using the units approach ....

At first,
Bin --> 3 units + 3
Wei --> 8 units + 8
After Wei gave 8 specimen to Bin,
Bin --> 3 units + 11
Wei --> 8 units
Bin had 1/2 of Wei's specimen :
3 units + 11 --> 4 units
1 unit = 11
3 x 11 + 3 = 36
Bin had 36 at first.

cheers.

[simple88]

Hi Tianzhu and MathIzzzFun,


You both have been most helpful. Thank you very much!

[ozora]

Need help for this question:I bought equal number of books of 2 titles, one is at $30 each and the other is at $40 each. If I spent equal amount of money on the two titles, I would have 1 book extra. Calculate the ant of money that I spent on buying those books .

[mrswongtuition]

http://i44.tinypic.com/2pyvxw5.jpg\">

[kyy]

Appreciate some help to solve the following question. Thanks!


Irene went to the supermarket with some money. If she bought 21 kg of sugar, she would need another $27, If she bought 8 kg of sugar, she would have $12 left. How much does $1kg of sugar cost?

[mrswongtuition]

http://i42.tinypic.com/21jsobc.jpg\">

[MathIzzzFun]

ozora:

Need help for this question:I bought equal number of books of 2 titles, one is at $30 each and the other is at $40 each. If I spent equal amount of money on the two titles, I would have 1 book extra. Calculate the ant of money that I spent on buying those books .

Hi

alternate approach using inverse relation between price and quantity...

http://i40.tinypic.com/11spf6o.png\">

cheers.

[ozora]

Thanks mrs Wong n mathsizzzfun