Jamesbond:

The mass of rice in bag B was 0.25 the mass of rice in bag A at first. After 105 kg of the rice in bag A and 20 kg 300 g of rice in bag B was used, the mass of rice in bag A was 1/2 the mass of rice in bag B.

a) How much rice was left in bag B at the end?
b) What was the total mass of rice in bag A and bag B at first?

Hi Jamesbond,

The answer for (a) is 6.8kg, and (b) 135.5kg.

Model, notes and workings can be found in the link below. Hope it helps.

http://www.flickr.com/photos/99739550@N08/9423945928/lightbox/

:hi5:

kiasuMay11:

http://i42.tinypic.com/2jdotuc.jpg\">

Pls help

Hi kiasuMay11,

If 1/5 of the triangle is shaded, then 4/5 of the triangle is unshaded.
If 2/7 of the square is shaded, then 5/7 of the square is unshaded

Using ratio:

Unshaded Shaded Unshaded
(Triangle) : (Overlap) : (Square) : Total
4 : 1 * : - : -
8 : 2 : - : - (1)
- : 2 : 5 : - (2)
8 : 2 : 5 : 15 **
*multiply this ratio by 2 to make the \"shaded portion\" of Triangle & Square the same in order to compare.

** Combine ratio (1) and (2) and you will get a total of 15 U (note that no double counting of the overlapping portion is involved)

a) Therefore 2/15 of the figure is shaded.

b) 2 U= 28 cubic cm, therefore 15 U= 210 cubic cm.

Hope this is clear.

Cheers!

jyee1:

Hihi, can anybody advise why is it not advisable to teach a P3 kids to solve Math problem using algebra method? Can anybody help with solving the following question in a logical way without using algebra. There are a total of 100 gals and boys. Gals get 5 sweets each, boys get 3 sweets each. Eventually, the total no. of sweets gals have is 164 more than the boys. How many gals are there?


Cheers

Hi jyee1,
I guess the most straight forward answer is that Algebra is not part of P3 syllabus. P3 math has not advanced to stage of establishing the relation between the proportion of Girls to Boys as per this question.
At their level, they are required to know the \"guess and check\" method (or \"trial and error\").

Let's start solving using Guess and Check.
We know there are a total of 100 B & G,
Formulate a simple table to start guessing and checking (literally!) to find the answer.

Do refer to this link for the table.

http://www.flickr.com/photos/99739550@N08/

Hope this helps.

Volume = 12cm x 10cm x 8cm =960cm cubed (Length x Breadth x Height)

Mass = 1kg

Now, to remove the mould, John will need to remove 1 cm from each of the 6 sides, that leads to 2cm from the Length, Breadth and Height.

Therefore the new Volume = 10cm x 8cm x 6cm = 480 cm cubed
Orig. Vol : New Vol
960 : 480
2 : 1

Orig. Mass : New Mass (change of the mass must be the same too!)
2 : 1
1000g : 500g

Hope this is clear enough…

hilarious and real!

i hope all our kids can grow up to be compassionate and gracious.