Q&A - PSLE Math

[ET-PH]

charsen:

superksmum:

Hi please help on this question (Henry Park Prelim 2011, question 16).


Mr Lee took 7 hours to travel from Town A to Town B while Mr Wong took 8 hours to travel from Town B to Town A. Both of them did not change their spped throughout the journey. Both of them started off at the same time and moved towards each other. 3 hours later, they were 110km apart. What was the speed Mr Lee was driving?

Thank you.

Hi
In 3 hours, lee drove 3/8 of the journey.At the same time,wong took 3/7 of the journey.So,we should make the denominators 8 and 7 to be 56 since the distance in both is common.

Lee travelled 24U and wong travelled 21U.
56u-24U-21U=11U
11U-110km
1U-110/11=10km
Distance lee travelled--->10x24=240km
Lee's speed------>240/3=80km/h(ANS)

Hi Charsen,

I stuck with this question too, can you explain how you get 3/8 of the journey for Lee and 3/7 of the journey for Wong. Thanks.

[ET-PH]

Hi, I need help on HPPS 2011 Prelim Qn 17.


There were 1000 students at the parade ground and indoor sports hall. 40% of the 600 students at the parade ground were girls. 60% of the students at the indoor sports hall were girls. After some students in both the venues moved from one venue to the other, 30% of the students in the parade ground and 70% of the students at the indoor sports hall were girls. How many students were there in the indoor sports hall after the movement had taken place ? Thanks.

[MathIzzzFun]

ET-PH:

Hi, I need help on HPPS 2011 Prelim Qn 17.


There were 1000 students at the parade ground and indoor sports hall. 40% of the 600 students at the parade ground were girls. 60% of the students at the indoor sports hall were girls. After some students in both the venues moved from one venue to the other, 30% of the students in the parade ground and 70% of the students at the indoor sports hall were girls. How many students were there in the indoor sports hall after the movement had taken place ? Thanks.

this was discussed - http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&start=7690

cheers.

[MathIzzzFun]

ET-PH:

charsen:

Hi please help on this question (Henry Park Prelim 2011, question 16).


Mr Lee took 7 hours to travel from Town A to Town B while Mr Wong took 8 hours to travel from Town B to Town A. Both of them did not change their spped throughout the journey. Both of them started off at the same time and moved towards each other. 3 hours later, they were 110km apart. What was the speed Mr Lee was driving?

Thank you.
Hi
In 3 hours, lee drove 3/8 of the journey.At the same time,wong took 3/7 of the journey.So,we should make the denominators 8 and 7 to be 56 since the distance in both is common.

Lee travelled 24U and wong travelled 21U.
56u-24U-21U=11U
11U-110km
1U-110/11=10km
Distance lee travelled--->10x24=240km
Lee's speed------>240/3=80km/h(ANS)

Hi Charsen,

I stuck with this question too, can you explain how you get 3/8 of the journey for Lee and 3/7 of the journey for Wong. Thanks.

there is a typo error... Mr Lee travelled 3/7 of journey, Mr Wong travelled 3/8 of journey

Distance between AB --> 56 units
Mr Lee took 7 hours to travel from A to B,
so in 3 hours, distance travelled --> 3/7 x 56 units = 24 units

Mr Wong took 8 hours to travel from B to A
so, in 3 hours, distance travelled --> 3/8 x 56 units = 21 units

Total distance between A & B
= 21 units + 24 units + 110 km --> 56 units
11 units --> 110 km
1 unit --> 10 km
Mr Lee's speed --> distance AB/ time to travel AB = 56 x 10 / 7 = 80 km/h

cheers.

[MathIzzzFun]

Bunny27:

Hi, can someone pls help on this question


1. Habri had some 20cents coins and 50cents coins.
He spent 1/4 of his 20cents coins and 40% of his 50cents coins.
The value of 20cents coins left was the same as the value of 50cents coins left. If the difference between the value of 20cents coins and the value of 50cents coins he had at first was $12, how much did Habri have at first?

TIA

3/4 of value of 20-cent coins = 3/5 of value of 50-cent coins
At first,
value of 20-cent coins : value of 50-cent coins --> 4u : 5u -- total value --> 9u
1u --> $12
Total amount of money Habri had at first --> 9 x $ 12 = $108

cheers.

[tianzhu]

Hi girl


Good Morning.

For Q2, it’s an interesting question.

You may solve it with strategies taught in your school.

1) Systematic Listing
2) Observe the pattern.

Now, tweak the question a bit if you want to try something new, instead of forty page newspaper, use a twenty six-page newspaper.

A twenty six- page newspaper, which consists of only one section, has a sheet with page 9 and page 10 missing. What other pages are missing?

For your easy reading, I’ve added in the solution for the cards posted yesterday.

Have a smooth journey towards PSLE 2012.

Best wishes

http://farm8.staticflickr.com/7126/7843764404_24a76a1abb_z.jpg\">

http://farm9.staticflickr.com/8440/7836643020_0af55760ca_z.jpg\">

[Tiramisu Coco]

tianzhu:

Tiramisu Coco:

Hi, pls help with this qtn. Thks!


http://m.flickr.com/photos/82618212@N07/7837766706/lightbox/

Hi

A similar question has been discussed in one of the earlier posts, but I can't locate it now.

There are a few ways to solve it.

One possible way.

Radius of circle -------( a+b-c)/2 -------(18+24-30)/2 ------ 6 cm

Best wishes

Hi Tianzhu, thks for your reply.
This qtn has not been discussed before, think u refer to the wrong qtn on the photostream. It's the last item abt ABCD is a square of 20cm. E & F are the mid-points of AB & AD. Find area of shaded region.
Would appreciate your help for this qtn. TIA

[tianzhu]

Tiramisu Coco:

Hi Tianzhu, thks for your reply.

This qtn has not been discussed before, think u refer to the wrong qtn on the photostream. It's the last item abt ABCD is a square of 20cm. E & F are the mid-points of AB & AD. Find area of shaded region.
Would appreciate your help for this qtn. TIA

Hi

When I clicked on your link, all I could see was a circle inscribed in a triangle.

Based on your description, perhaps this question may help.

Q15 of this paper, please go to page 35 of this link.

http://www.orlesson.org/orp/10Ma/2010-P6-Math-SA2-Rosyth.pdf

Best wishes.

http://farm5.staticflickr.com/4103/5037820252_8aa41e056c_z.jpg\">

[tianzhu]

Robertpattinsonidle:

Please help me. how to solve these types of qsns? http://i47.tinypic.com/65v0aw.jpg\">

Hi

Questions on \"nets\" are pretty challenging.

I am more inclined to go for (3).

Best wishes

[kuts]

A B C D


2 3 4 5
9 8 7 6
10 11 12 13

If this pattern continues, in which column will number 801 appear?

Please help!