Q&A - PSLE Math

[Tang]

Despair:

Sorry for the trouble, five tough questions,


1. Mr Foo started to travel from Town P to Settlement Q on his limousine at 10 30 at an average speed of 48km/h. After taking a rest for 45 min, he continued travelling from Settlement Q to City R at an average speed that was 1.5 times his earlier average speed. He arrived at City R at 15 00. Given that the distance between Settlement Q and City R is 30 km less than the distance between Town P and Settlement Q, find the distance between Town P and City R.

Hi,

Time from 1030 to 1500 = 4 1/2 h

4 1/2 - 45/60 = 3 3/4 h

1.5 = 3/2

30/48 = 5/8 h

[ ][ ][ ][5/8][ ][ ]

5 u --> 3 3/4 - 5/8 = 3 1/8 h
3 u --> 3/5 x 3 1/8 = 1 7/8 h

48 x 1 7/8 = 90 km

90 x 2 + 30 = 210 km

[tianzhu]

Hi


Hope this helps.

Best wishes.

http://farm7.static.flickr.com/6063/6139917034_a6c214361a_z.jpg\">

[ms_lim]

MathIzzzFun:

ivanhoo99:

Hi pls help


Mr Tan drove from city X to city Y.At the same time,Mr Koh drove from city Y to city X.They passed each other 64 km away from city Y and continued their journeys. They made a u-turn upon reaching their destinations so that they could return to their own cities. They passed each other again 52 km away from city X.. Find the distance between the two places when they met each other.

This question has been posted much earlier but can't seem to find the solution..

Hi

http://www.flickr.com/photos/62167097@N02/6085706330/in/photostream

cheers.

Dear MathIzzzFun, can you help to explain why the distance travelled by Mr Koh from A to B = 2 x 64km = 128km?

[MathIzzzFun]

ms_lim:

MathIzzzFun:

Hi

http://www.flickr.com/photos/62167097@N02/6085706330/in/photostream

cheers.

Dear MathIzzzFun, can you help to explain why the distance travelled by Mr Koh from A to B = 2 x 64km = 128km?

Hi

After they first meet at A, Mr Koh travelled from A-X-B and Mr Tan travelled from A-Y-B, and the total distance travelled ie A-X-B + A-Y-B, is 2XY

It is assumed that both Mr Tan and Mr Koh travelled at constant speed throughout their journeys, Mr Koh travelled 64km in the first part of journey (total distance =XY), and since total distance travelled in the 2nd part of the journey is 2XY, and he would travel 2 x the distance which is 2 x 64km

cheers.

[ms_lim]

MathIzzzFun:

ms_lim:

[quote=\"MathIzzzFun\"]

Hi

http://www.flickr.com/photos/62167097@N02/6085706330/in/photostream

cheers.

Dear MathIzzzFun, can you help to explain why the distance travelled by Mr Koh from A to B = 2 x 64km = 128km?

Hi

After they first meet at A, Mr Koh travelled from A-X-B and Mr Tan travelled from A-Y-B, and the total distance travelled ie A-X-B + A-Y-B, is 2XY

It is assumed that both Mr Tan and Mr Koh travelled at constant speed throughout their journeys, Mr Koh travelled 64km in the first part of journey (total distance =XY), and since total distance travelled in the 2nd part of the journey is 2XY, and he would travel 2 x the distance which is 2 x 64km

cheers.[/quote] :thankyou: MathIzzzFun for your detailed explanation.

[Andrew Lee]

Hi


please clean up the pic.. difficult to figure out where are the x,y, z... if these are lying on the same straight line then there is no definite answer for x,y,z (y+z=180)... because the line DEF is not anchored.

cheers.[/quote]

So sorry. I already clean up the pic, hope you can see it

http://i56.tinypic.com/hvdro2.jpg\">

[Andrew Lee]

http://i54.tinypic.com/rcshzd.jpg\">[/quote]


Hi

please check question ...

http://i52.tinypic.com/30ug1e0.jpg\">

It is \"a\"..but then how to get (a) answer?
Hi

the question is flawed.

cheers.[/quote]

Can explain why which part of this question is flawed?

[MathIzzzFun]

Andrew Lee:

Hi


please clean up the pic.. difficult to figure out where are the x,y, z... if these are lying on the same straight line then there is no definite answer for x,y,z (y+z=180)... because the line DEF is not anchored.

cheers.

So sorry. I already clean up the pic, hope you can see it

http://i56.tinypic.com/hvdro2.jpg\">[/quote]

Hi

there is no definite solution because the line DEF is not anchored - x can take any value from 0 to 108 and y+z = 180.

cheers.

[MathIzzzFun]

Andrew Lee:

http://i54.tinypic.com/rcshzd.jpg\">

Hi

please check question ...

http://i52.tinypic.com/30ug1e0.jpg\">

It is \"a\"..but then how to get (a) answer?
Hi

the question is flawed.

cheers.[/quote]

Can explain why which part of this question is flawed? [/quote]

hi

the angle DGH is 180 deg, so DGH is a straight line !! and not angled as shown.

cheers.

[looking4Tutor]

I have a long list of questions :oops: -


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TIA