Q&A - P5 Math

[tianzhu]

Hi Xiao Hu


I took another look at the overlapping question.

The length of the rectangle is 16cm (same as before).

The area of the shaded area is 24 sq cm (same as before).

Total area of the unshaded area is 212 sq cm (different).

To avoid confusion, I’ve removed all my earlier posts on this question.

Best wishes

[SAHMwith2boys]

Hi all, encountered the below maths question and need help:


Machine A can produce 450 toys in 5 hours and Machine B can produce 120 less toys in 3 hours. Find the ratio of the number of toys produced by Machine A to the number of toys produced by Machine B every hour.

Would appreciate if explanation and working can be given as well so that I can have a better understanding...thanks a lot... :oops:

[elderflowertea]

Which part of Singapore do you stay at? I am a full time tutor giving tuition at my house area.

[tianzhu]

SAHMwith2boys:

Hi all, encountered the below maths question and need help:


Machine A can produce 450 toys in 5 hours and Machine B can produce 120 less toys in 3 hours. Find the ratio of the number of toys produced by Machine A to the number of toys produced by Machine B every hour.

Would appreciate if explanation and working can be given as well so that I can have a better understanding...thanks a lot... :oops:

Hi

Good Morning.

Machine A

5h ------ 450 toys
1h ------ 90 toys

Machine B

3h ------ 330 toys (450-120)
1h ----- 110 toys

Machine A : Machine B ------ 90:110 ------ 9:11

Best wishes

[Jamesbond]

1) Dan spent 2/3 of her money on some gaming accessories. She spent 3/7 of the remaining money on a box of colour pencils and the remaining $24 on a CD game.

a) What fraction of her money was spent on the CD?
b) How much money did Dan have at first?

2) Imu gave 2/7 of his salary to his wife and used 1/3 of his remaining money to pay his bills. Given that he had left $2200 for himself, find the salary of Imu?

Pl explain me in detail. vvv diff…Thanks in advance.

[SAHMwith2boys]

tianzhu:

SAHMwith2boys:

Hi all, encountered the below maths question and need help:


Machine A can produce 450 toys in 5 hours and Machine B can produce 120 less toys in 3 hours. Find the ratio of the number of toys produced by Machine A to the number of toys produced by Machine B every hour.

Would appreciate if explanation and working can be given as well so that I can have a better understanding...thanks a lot... :oops:

Hi

Good Morning.

Machine A

5h ------ 450 toys
1h ------ 90 toys

Machine B

3h ------ 330 toys (450-120)
1h ----- 110 toys

Machine A : Machine B ------ 90:110 ------ 9:11

Best wishes

Thanks TianZhu...

[Jamesbond]

1) Dan spent 2/3 of her money on some gaming accessories. She spent 3/7 of the remaining money on a box of colour pencils and the remaining $24 on a CD game.

a) What fraction of her money was spent on the CD?
b) How much money did Dan have at first?

2) Imu gave 2/7 of his salary to his wife and used 1/3 of his remaining money to pay his bills. Given that he had left $2200 for himself, find the salary of Imu?

Pl explain me in detail. vvv diff…Thanks in advance.

[CRAZYBANANA]

1) Dan spent 2/3 of her money on some gaming accessories. She spent 3/7 of the remaining money on a box of colour pencils and the remaining $24 on a CD game.

a) What fraction of her money was spent on the CD?
$24 = 4/7 of the remaining $
7 unit represents 1/3 of her $
At first, she would have 21 units
Therefore, the fraction is 4/21

b) How much money did Dan have at first?
1 unit = $24/4 = $6
21 unit x $6 = $ 126



2) Imu gave 2/7 of his salary to his wife and used 1/3 of his remaining money to pay his bills. Given that he had left $2200 for himself, find the salary of Imu?
He used 1/3 of 5/7 to pay bills.
He is left with 2/3 x 5/7 = 10/21
1 unit = $2200 / 10 = $220
His salary = 21 x $220 = $4620

[Jamesbond]

thanks a lot

[savoury sweet]

Jamesbond:

1) Dan spent 2/3 of her money on some gaming accessories. She spent 3/7 of the remaining money on a box of colour pencils and the remaining $24 on a CD game.

a) What fraction of her money was spent on the CD?
b) How much money did Dan have at first?

2) Imu gave 2/7 of his salary to his wife and used 1/3 of his remaining money to pay his bills. Given that he had left $2200 for himself, find the salary of Imu?

Pl explain me in detail. vvv diff...Thanks in advance.

HI

As I am still new in this KSparents forum, therefore I have no idea how to post the solution in model method and my scanner is down. So I will try my best in explaining them to you in words instead.

1) Draw 3 units(3/3) in a model. Highlight the last 2 units to indicate spent on gaming accessories also means 2/3 . Therfore you have 1 unit left(1/3).

Bring down the 1/3 model which is the remaining money. Then you have to draw 7 units in that 1/3 model and highlight or shade 3 units (3/7) to indicate the amount spent on a box of color. The remaining 4/7 = $24 is the amount spent on CD games.

The fraction of Dan's money spent on CD is 4/7 x 1/3 = 4/21.


b) 4/7 = $24

----- 4u = 24
----- 1u = 24 / 4 = $6
----- 7u = $6 x 7 = $42

$42 x 3 = $126 is the amount Dan had at first.



2) The method is abt the same, so I just write down the number statement.

7/7 -2/7(given to wife)=5/7 (remaining)
5/7 is also equals to 3/3 as the qns states that Imu used 1/3 to pay bills.

So u have to draw 3 units of model and shade off 1 unit indicating pay bills.

Left with 2 units = $2200
1 units = $1100, so the entire 3units = $3300

the 3 units is also equals to the remaining 5/7 of the main model.
therfore ie 5 units = $3300
1 units = $660, the whole salary of Imu is 7 units---$660 x 7
=$4620


Hope you understand the above.