Q&A - PSLE Math

[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: -


http://i55.tinypic.com/1yr53d.jpg\">

http://i53.tinypic.com/15duxxx.jpg\">

http://i51.tinypic.com/2wrhumo.jpg\">

http://i54.tinypic.com/15nansw.jpg\">

http://i53.tinypic.com/2gxpqoo.jpg\">

http://i55.tinypic.com/24fbfj8.jpg\">

http://i52.tinypic.com/25aqjpe.jpg\">

http://i54.tinypic.com/2u6hf1s.jpg\">

TIA

[tianzhu]

looking4Tutor:

http://i55.tinypic.com/1yr53d.jpg\">

Hi

Observe the pattern.

1*3
2*4
3*5

The sequence is formed by multiplying the figure number with (figure number +2)

n* (n+2)

(a) 7*9 ----- 63

(b) 80*(80+2) ----- 6560

(c) This one a bit tricky for PSLE kids, never mind about learning to solve the equation. Think logically and use GC.

With calculators, actually not too tedious.4355 is less than 6560, so figure number must be less than 80.

Try 70, wrong.Try 65, bingo that’s correct

65(65+2) -----4355

The answer is figure 65.

Best wishes