Q&A - PSLE Math

[small]

tianzhu:

Thank you for your help.


Quite an interesting question, the answer hinges on how we would interpret together took

Mr Yoma and Mr Ula together took 5 hours to paint a room.
Mr Wara and Mr Hito together took 4 hours to paint the same room.
Mr Ula and Mr Wara together took 3 hours to paint the same room.
How long would both Mr Yoma and Mr Hito together take to paint the same room?

Take the case of Mr Yoma and Mr Ula, do you interpret as both men were painting for a total duration of 5 hours. (T1+T2 =5)
or they were painting for 5 hours each (T1=5 and T2 =5)?

Hi tianzhu,

I will interpret as the both men were painting for a total duration of 5 hours, so the answer is 6 hours???

[Dharma]

small:

tianzhu:

Thank you for your help.


Quite an interesting question, the answer hinges on how we would interpret together took

Mr Yoma and Mr Ula together took 5 hours to paint a room.
Mr Wara and Mr Hito together took 4 hours to paint the same room.
Mr Ula and Mr Wara together took 3 hours to paint the same room.
How long would both Mr Yoma and Mr Hito together take to paint the same room?

Take the case of Mr Yoma and Mr Ula, do you interpret as both men were painting for a total duration of 5 hours. (T1+T2 =5)
or they were painting for 5 hours each (T1=5 and T2 =5)?

Hi Tianzhu and small,

Yoma and Ula took 5 hrs to complete painting the room. T1 + T2 = 5 is not right. You need not bother abt time taken by either Yoma or Ula to paint because their rate of painting are different.

Just take the combinations of times taken by the different groups of men to complete the room.

In 1 hr:
Y+U - 1/5 of room
W+H - 1/4 of room
U+W - 1/3 of room

Therefore, if 4 of them paint together,

In 1 hr:
Y+U+W+H = 1/5 + 1/4 = 9/20 of room

So, Y + H will complete (9/20 - 1/3) = 7/60 of room in 1 hr

So, Y & H will complete painting the room in 60/7hrs

[tianzhu]

small:

I will interpret as the both men were painting for a total duration of 5 hours, so the answer is 6 hours???

The answer is spot on if based on your interpretation.However, the given answer is the same as what Dharma has interpreted.

I am confused.Consider these two sentences.

Mr Yoma and Mr Ula together took 5 hours to paint a room.

Mr Yoma and Mr Ula took 5 hours to paint a room.

Do they have the same meaning in context?Or, do they mean different things?

[Dharma]

tianzhu:

small:

I will interpret as the both men were painting for a total duration of 5 hours, so the answer is 6 hours???

The answer is spot on if based on your interpretation.However, the given answer is the same as what Dharma has interpreted.

I am confused.Consider these two sentences.

Mr Yoma and Mr Ula together took 5 hours to paint a room.

Mr Yoma and Mr Ula took 5 hours to paint a room.

Do they have the same meaning in context?Or, do they mean different things?

From your question, I interprete as with both Mr Yoma and Mr Ula in a room where they (together) took 5 hrs to complete painting the whole room. That's my inpretation of your 1st sentence ...\"together took\"

The 2nd sentence means the same as the 1st one ...I think!!!!

[small]

Hi Dharma,


Once again thanks a lots for the solution…

[Tang]

P6 pupils may want to try the Maths Questions at Uncle Observer's blog


http://prischoolmaths.blogspot.com/

[Denise]

Jack bought some pens and erasers for a total of $100.10.

He spent $9.10 more on the pens than the erasers.
Each pen costs $3.70 more than each eraser.
Jack bought 6 times more ereasers than pens. How much does each pen cost?

[mrswongtuition]

I'm not sure if this is right, but based on my interpretation of the question:


Quantity of P:E is 1:7
P [__]
E [__][__][__][__][__][__][__]

Price of P & E (in total)
P [_______][_$9.10_] ````` } Total
E [_______] ````````````` }$100.10

By Price:
$100.10 - $9.10 = $91
2u -> $91
1u -> $45.50

Since there are 7 units of erasers, each unit of erasers will cost $45.50/7 = $6.50

The price of the pens is $45.50 + $9.10 = $54.60

Price of pens take away the price of 1 unit of erasers (to find the difference in amount if the same amount of pens & erasers were bought):
$54.50 - $6.50 = $48.10

Since each pen is more expensive than each eraser by $3.70,
$48.10/$3.70 = 13 pens

To find the price of each pen:
$54.60/13pens = $4.20

[Dharma]

Denise:

Jack bought some pens and erasers for a total of $100.10.

He spent $9.10 more on the pens than the erasers.
Each pen costs $3.70 more than each eraser.
Jack bought 6 times more ereasers than pens. How much does each pen cost?

Its correct

[Dharma]

mrswongtuition:

I'm not sure if this is right, but based on my interpretation of the question:

Sorry ...the answer is right