Q&A - P4 Math

[chloecube]

i see, ok thks alot everyone

[Nebbermind]

chloecube:

thks thein,


so the number of boxes have to be the same?

sorry for being slow, i am trying to understand what the question is asking. they ask for the number of marble and not boxes, so i thought the differences in boxes does not matter.

if i take 38 marbles ; mof 6 wil have 6 boxes and mof of 7 will have 7 boxes..
but if i take 80 marbles, number of boxes will be the same

i am confusing myself..

I was confused too when I 1st read this qn coz how can it be 11 short if u group them into 7s. Then I realised the no. of boxes MUST be kept the same in this qn.

[chloecube]

Nebbermind:

chloecube:

thks thein,


so the number of boxes have to be the same?

sorry for being slow, i am trying to understand what the question is asking. they ask for the number of marble and not boxes, so i thought the differences in boxes does not matter.

if i take 38 marbles ; mof 6 wil have 6 boxes and mof of 7 will have 7 boxes..
but if i take 80 marbles, number of boxes will be the same

i am confusing myself..

I was confused too when I 1st read this qn coz how can it be 11 short if u group them into 7s. Then I realised the no. of boxes MUST be kept the same in this qn.

thks!
so can i conclude that model drawing is better than using multification?

[tianzhu]

chloecube:

so can i conclude that model drawing is better than using multification?

Hi

Whether you go the MD or MM way, the answer should be the same.

Just like porridge, some like it hot, some like it cold.

There are many ways to solve such questions and students should choose the method they are comfortable with.

Best wishes

[Nebbermind]

chloecube:

thks!

so can i conclude that model drawing is better than using multification?

Actually this qn is a very good sample for this kind of grouping qn, albeit a bit confusing. This is because u DO NOT need to remember any formula for this qn (this level of difficulty).

If u put 6 into each box, u get 2 extra. Then u put 7 into the boxes. and short of 11.

Visualize adding the 2 'extras' into the 1st 2 boxes. If u still need 11 more to completely make them boxes of '7', there are (2 + 11) boxes, ya?

If u are short of 4, then there would be (2 + 4) boxes.

[AgonyMum]

Hi, need guidance and enlightenment with these 2 questions.Pls help.Thanks in advance.


I can solve them using Guess and Check but is there a better and more efficient method?

Qn1. Every 10 children shared a big plate of fried rice and every 8 children shared a big plate of chicken wings. If 9 plates were used altogether, how many children were there?

Qn2. Ahmad has 20 toy wheels. He wants to make some model toy cars and motorcycles.How many of each type of toys can he make using all the 20 wheels? How many different answers can you find?

[AgonyMum]

Hi, must use simple Algebra to solve these questions.Pls guide.Thanks in advance!


Qn1. When Tim packed some apples into plastic bags in the morning, he had 7 bags of equal number of apples and 5 extra apples. By evening, many apples had gone bad. Then, he had only 3 plastic bags of good apples and 45 bad apples. If he packed the same number of apples into each bag, how many apples were there in each bag?

Qn2. Sherry and Steven went fishing. By noon, Steven had caught 24 more fish than Sherry. After lunch break, both of them only managed to catch 1 more fish each. At the end, Steven had 4 times as many fish as Sherry. Find out how many fish Steven caught before noon.

Qn3. Ashley and Mindy have some balls.If Ashley gave Mindy 10 balls, Ashley would have 10 more balls than Mindy. If Mindy gave Ashley 15 balls, Ashley would have 4 times as many balls as Mindy. Find out how many balls Ashley and Mindy have respectively.

[Thein]

Qn1. When Tim packed some apples into plastic bags in the morning, he had 7 bags of equal number of apples and 5 extra apples. By evening, many apples had gone bad. Then, he had only 3 plastic bags of good apples and 45 bad apples. If he packed the same number of apples into each bag, how many apples were there in each bag?



7x + 5= 3x + 45
4x = 40
x = 10

10 apples in each bag

[Thein]

Qn2. Sherry and Steven went fishing. By noon, Steven had caught 24 more fish than Sherry. After lunch break, both of them only managed to catch 1 more fish each. At the end, Steven had 4 times as many fish as Sherry. Find out how many fish Steven caught before noon.


By noon Steven = Sherry + 24

After lunch break Steven = Steven + 1
Sherry = Sherry+1;

Steven = 4 X Sherry
Sherry + 24 = 4 X Sherry
3 X Sherry = 24
Sherry = 8
Steven = 32
Hence before noon Steven caught 32-1=31 fishes and Sherry caught 7 fishes.

[Thein]

Qn3. Ashley and Mindy have some balls.If Ashley gave Mindy 10 balls, Ashley would have 10 more balls than Mindy. If Mindy gave Ashley 15 balls, Ashley would have 4 times as many balls as Mindy. Find out how many balls Ashley and Mindy have respectively.


Ashley - 10 = Mindy + 10 + 10_________________ (1)

4 X (Mindy - 15) = Ashley + 15__________________(2)

From (1) Ashley = Mindy + 30;

Substitute in (2)

4 X (Mindy - 15) = Mindy + 30 + 15

4 X Mindy - 60 = Mindy + 45

3 X Mindy = 105

Mindy = 35 balls

Ashley = 65 balls

Check:(i)Ashley gave 10 balls to Mindy; Ashley = 65-10 = 55;
Mindy = Mindy + 10 = 45;

Ashley - Mindy = 10;

(ii)Mindy gave 15 Ashley 15 balls; Mindy = 35 - 15 = 20
Ashley = 65 + 15 = 80;

Ashley = 4 X Mindy = 4 X 20 = 80