Q&A - P5 Math

[tianzhu]

happyheart:

One more questions, thank you again in advance whoever can help


Brandon had 30 spelling tests and collected 36 games cards. With every full marks he scored for a spelling test, he received 2 games cards from his teacher. When he did not score full marks, he had to return 1 games card.

a) how many spelling tests did brandon score full marks?
b) if Brandon wanted to receive a total of 51 games cards, how many spelling tests could he afford not to score full marks?

Hi

You may use “Make a Supposition” or “Assuming Method”

Assuming Brandon scored full marks for all 30 spelling tests.

30*2 ------ 60

For every test which he didn’t score full marks, he lost (2+1) --- 3 games cards.

60 - 36 --- 24
24/3 --- 8

30 - 8 ------ 22 (spelling tests with full marks).

60 – 51 ------ 9

9/3 -----3 (tests w/o full marks)

Best wishes

[Udon]

Thank you mummyv for helping me the 3 Maths questions....

[keinic]

Hi


I need help for the following:

Classes 5A and 5B have the same number of pupils. The ratio of the no. of boys in 5A to the no. of boys in 5B is 2:3. The ratio of the no. of girls in 5A to the no. of girls in 5B is 7:4.

a.)Find the ratio of the no. of boys to the no. of girls in 5A
b.) if there are 15 fewer girls than boys in 5B, how many pupils are there in 5B?

TIA.

[MathIzzzFun]

keinic:

Hi


I need help for the following:

Classes 5A and 5B have the same number of pupils. The ratio of the no. of boys in 5A to the no. of boys in 5B is 2:3. The ratio of the no. of girls in 5A to the no. of girls in 5B is 7:4.

a.)Find the ratio of the no. of boys to the no. of girls in 5A
b.) if there are 15 fewer girls than boys in 5B, how many pupils are there in 5B?

TIA.

Hi

http://www.flickr.com/photos/62167097@N02/5760364658/in/photostream

cheers.

[keinic]

Hi MathIzzzFun,


Thank you so much for the well-illustrated solution!

Cheers.

[keinic]

Hi


My DS has diffculty in understanding the model solution provided for the following. I’m thinking if someone could help to explain it more simply. TIA.

Mr Lee’s salary to Mr Tan’s salary is in the ratio of 8:5. Mr Lee saves $240 while Mr Tan saves $270. If Mr Lee’s expenditure to Mr Tan’s expenditure is in the ratio 8:3, what is Mr Tan’s salary?

[tianzhu]

keinic:

Hi


My DS has diffculty in understanding the model solution provided for the following. I'm thinking if someone could help to explain it more simply. TIA.

Mr Lee's salary to Mr Tan's salary is in the ratio of 8:5. Mr Lee saves $240 while Mr Tan saves $270. If Mr Lee's expenditure to Mr Tan's expenditure is in the ratio 8:3, what is Mr Tan's salary?

Hi

Good Morning.

Another alternative to MD is to use “Units and Parts”

Salary ------ expenditure + saving

Mr Lee's expenditure to Mr Tan's expenditure ------- 8 units: 3 units

Mr Lee's saving to Mr Tan's saving ------- 240: 270

Mr Lee's salary to Mr Tan's salary ------- 8 parts:5parts

Equalise the parts or cross multiply.

8 units + 240 ------- 8 parts
(x5)
40 units + 1200 ------- 40 parts

3 units + 270 ------- 5 parts
(x8)
24 units + 2160 ------- 40 parts

40 units + 1200 ------- 24 units + 2160
16 units ------- 960
1 unit ------ 60

Mr Tan’s salary ------(3*60) + 270 -------450

Best wishes

[keinic]

Good morning, Tianzhu. Tks a million

[speedmaths.012624com]

keinic:

Hi


My DS has diffculty in understanding the model solution provided for the following. I'm thinking if someone could help to explain it more simply. TIA.

Mr Lee's salary to Mr Tan's salary is in the ratio of 8:5. Mr Lee saves $240 while Mr Tan saves $270. If Mr Lee's expenditure to Mr Tan's expenditure is in the ratio 8:3, what is Mr Tan's salary?

Hi,

You may try using the Advanced Model Method (or Bags and Boxes):

Mr Lee's salary to Mr Tan's salary is in the ratio of 8:5.
Let Mr Lee put his salary into 8 Bags.
Let Mr Tan put his salary into 5 Bags.

The amount of money in each of the 13 bags are the same.

Let Mr Lee take $240 (savings) from the 8 Bags, and put the remainder into 8 Boxes (expenditure).

Let Mr Tan take $270 (savings) from the 5 Bags, and put the remainder into 3 Boxes (expenditure).

The amount of money in each of the 11 Boxes are the same.

Salary = Savings + Expenditure

Mr Tan:
5 Bags = $270 + 3 Boxes
(x
40 Bags = $2160 + 24 Boxes

Mr Lee:
8 Bags = $240 + 8 Boxes
(x 3)
24 Bags = $720 + 24 Boxes

40 Bags = $2160 + 24 Boxes\t(Row 1)
24 Bags = $720 + 24 Boxes\t\t(Row 2)

(Row 1 – Row 2)
16 Bags = $1440 + 0 Boxes\t
16 Bags = $1440\t
1 Bag = $1440 / 16 = $90
5 Bags = 5 x $90 = $450 (Mr Tan’s salary)

Hope this helps.

We will demonstrate this method at our Parents’ Workshop.
Please see thread on the Happenings forum.

Cheers


speedmaths.com

[MathIzzzFun]

keinic:

Hi


My DS has diffculty in understanding the model solution provided for the following. I'm thinking if someone could help to explain it more simply. TIA.

Mr Lee's salary to Mr Tan's salary is in the ratio of 8:5. Mr Lee saves $240 while Mr Tan saves $270. If Mr Lee's expenditure to Mr Tan's expenditure is in the ratio 8:3, what is Mr Tan's salary?

Hi

using MD...

http://i45.tinypic.com/35lu2kz.png\">

cheers.