Q&A - P5 Math

[MathIzzzFun]

NewMum2012:

You quoted \"area of triangle PRV + area of triangle QSV

= 1/2 area of rectangle PQRS\"

Can you please explain how this is possible?

Thanks for your prompt response!

Hi
Area of triangle PVR =area of triangle PVS (same base PV & same height PS=QR)
Area of triangle PVS + area of triangle QVS= 1/2 area of rectangle PQRS
so, area of triangle PVR + area of triangle QVS = 1/2 area of rectangle PQRS

cheers.

[cimman]

this question has been answered before:

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=71&t=6373&start=740

quite some time ago, that is.

[cimman]

this question was answered before:

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=71&t=6373&start=740

you should try the other question (the double square question) as well. it's also an interesting question.

[happyheart]

Hi, can someone help with this question please?


Jason and Muthu had some cards. During a game, Jason lost 1/4 of his cards to Muthu in the first round. In the second round, Muthu lost 1/3 of his cards to Jason. In the third round, Jason lost 1/6 of his cards to Muthu. At the end of the three rounds, Jason had 420 cards and Muthu had 744 cards left respectively. How many cards did Jason have at first?

Thank you.

[tianzhu]

happyheart:

Hi, can someone help with this question please?


Jason and Muthu had some cards. During a game, Jason lost 1/4 of his cards to Muthu in the first round. In the second round, Muthu lost 1/3 of his cards to Jason. In the third round, Jason lost 1/6 of his cards to Muthu. At the end of the three rounds, Jason had 420 cards and Muthu had 744 cards left respectively. How many cards did Jason have at first?

Thank you.

Hi

In working out this question, one key point to take note is that the number of cards stays the same throughout.

Work backwards.

5 units (5/6) ------ 420

1 unit ------ 84

6 units (6/6) ------- 504

You may continue with the rest of the calculations.

Hope this helps.

Best wishes

http://farm8.staticflickr.com/7236/7344390536_69246f67b8_z.jpg\">

[Easy-going]

Hi

can anybody pls help me with this sums? I am really at a lost.

1. There were some flowers at a flower shop. The ratio of the number of roses to the number of tulips was 2:3. When 50 more roses and 30 more tulips were added, the ratio of the number of roses to the number of tulips became 5:6. How many flowers were there at first?

2 Mr Lim had some stickers and stamps for his class. The number of stickers was half as many as the number of stamps. After each pupil in the class had received 3 stickers and 8 stamps from Mr Lim, he had 39 stickers and 2 stamps left. What was the total number of stickers and stamps Mr Lim had at first?

[tianzhu]

Easy-going:

2 Mr Lim had some stickers and stamps for his class. The number of stickers was half as many as the number of stamps. After each pupil in the class had received 3 stickers and 8 stamps from Mr Lim, he had 39 stickers and 2 stamps left. What was the total number of stickers and stamps Mr Lim had at first?

Hi

This question has been discussed before.

Best wishes

http://farm8.staticflickr.com/7214/6994422784_250a9bcd20_z.jpg\">

[tianzhu]

Easy-going:

Hi

can anybody pls help me with this sums? I am really at a lost.
1. There were some flowers at a flower shop. The ratio of the number of roses to the number of tulips was 2:3. When 50 more roses and 30 more tulips were added, the ratio of the number of roses to the number of tulips became 5:6. How many flowers were there at first?

Hi

You may use “Units and Parts”

At first

Roses: Tulips ------ 2 units: 3 units

Change

Roses: Tulips ------ 50:30

In the end

Roses: Tulips ------ 5 parts: 6 parts

Equalise the parts

2 units + 50 -------- 5 parts
(x6)
12 units + 300 ------- 30 parts

3 units + 30 -------- 6 parts
(x5)
15 units + 150 ------- 30 parts

12 units + 300 ------- 15 units + 150
3 units ------ 150
1 unit ------- 50

Number of roses@first ------- 2*50 ------- 100
Number of tulips@first ------- 3*50 ------- 150

Altogether, there were 250 flowers.

Best wishes

[Maths Hub]

You might want to explore thinking skills in problem solving

Before 2 : 3
+50 +30
After 5 : 6
Note that tulip ratio has double so to simplify to 1 variable we substitute as follows
Before 4 units : 6 units
Change +50 +30
After 5 units + 25 : 6 units + 30
It is observed that 4 units + 50 = 5 units + 25 therefore 1 units = 25
Flowers at first 10 units = 250

[happyheart]

tianzhu:

happyheart:

Hi, can someone help with this question please?


Jason and Muthu had some cards. During a game, Jason lost 1/4 of his cards to Muthu in the first round. In the second round, Muthu lost 1/3 of his cards to Jason. In the third round, Jason lost 1/6 of his cards to Muthu. At the end of the three rounds, Jason had 420 cards and Muthu had 744 cards left respectively. How many cards did Jason have at first?

Thank you.

Hi

In working out this question, one key point to take note is that the number of cards stays the same throughout.

Work backwards.

5 units (5/6) ------ 420

1 unit ------ 84

6 units (6/6) ------- 504

You may continue with the rest of the calculations.




Hope this helps.

Best wishes

http://farm8.staticflickr.com/7236/7344390536_69246f67b8_z.jpg\">

Thank you Tianzhu for answering this question. Sorry, I am trying to understand but just cannot get it. In the 2nd round, how do we establish the number of cards Muthu has? Could you explain further?