Q&A - P3 Math

[SPI]

:? Why my question 3 shirt became 5 units? Typo error or ? My teacher said can use faction to solve this problem. Can teach me?

tianzhu:

SPI:

3 shirts cost as much as 5 blouse. Mrs Tan bought 2 such shirts and 4 blouses for $110. find the cost of 6 such shirts

Hi

A common multiple of 3 and 5 is 15.

Shirt ----- 5 units
Blouse ------ 3 units

(2*5) + (4*3) ------ 22 units
22 units ----- 110
1 unit ----- 5

1 shirt ------ $25
6 shirts ----- $150

Best wishes

:?

[tianzhu]

SPI:

Why my question 3 shirt became 5 units?

Hi

You may use MD to solve this question.

The bars representing the cost of the 3 shirts and 5 blouses should be of the same size.

Divide first bar into 3 parts to represent 3 shirts,
Divide the second bar into 5 parts to represent 5 blouses.

To compare we need to make the number of units the same. A common multiple 3 and 5 is 15.

Hence shirt ------ 5 units (1/3)
Blouse ------ 3 units (1/5)

Or if you prefer to work using simultaneous concepts, similar to “stars and moons’ type of questions

3S ------ 5B
6S ------ 10B

2S + 4B ------ 110
Multiply by 3 to give
6S + 12B ------ 330

10B + 12B ----- 330
22B ----- 330
1B ------15

10B -----150
Hence, 6S -------150

You may also choose to work by pictorial method instead of alphabet method.

Best wishes

[SPI]

ok thanks Tianzhu.

[MathIzzzFun]

SPI:

I need help on this. Thanks in advance.


3 shirts cost as much as 5 blouse. Mrs Tan bought 2 such shirts and 4 blouses for $110. find the cost of 6 such shirts

hi

hope this will help.


http://postimage.org/image/1f0olc8mc/

cheers.

[tianzhu]

SPI:

ok thanks Tianzhu.

Hi

You're welcome.

Best wishes

[hypergatak]

Dear Tian Zhu and parents


Need your help on how to present workings for these 2 questions:-

(a) There were three times as many cats as dogs at the pet clinic. After 13 cats had left and another 5 dogs came to the clinic, there were an equal number of cats and dogs in the end. How many cats are there at the clinic at first?
(b) Zachary is 10 years older than Douglas. In 4 years’ time, he will be twice as old as Douglas. How old is Zachary now?
Thanks.

[tianzhu]

Hi


Hope this helps.

Ok, got to go, I'll post the solution to the second question if there is no solution from other members at a later time.

Best wishes.

http://farm6.static.flickr.com/5303/5557416839_6a9a3c1697_z.jpg\">

[MathIzzzFun]

hypergatak:

Dear Tian Zhu and parents


Need your help on how to present workings for these 2 questions:-

(a) There were three times as many cats as dogs at the pet clinic. After 13 cats had left and another 5 dogs came to the clinic, there were an equal number of cats and dogs in the end. How many cats are there at the clinic at first?
(b) Zachary is 10 years older than Douglas. In 4 years' time, he will be twice as old as Douglas. How old is Zachary now?
Thanks.

Hi

Solution for Q2, hope it helps.


http://postimage.org/image/9139sf0k/

cheers.

[hypergatak]

Thanks, very well explained!

[MathIzzzFun]

hypergatak:

Thanks, very well explained!

you're welcome

cheers. :lol: