Q&A - PSLE Math

[soseducation]

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Requires the use of algebra. sorry answer is 560, write wrongly.

[belnanna]

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Requires the use of algebra. sorry answer is 560, write wrongly.

Hi SOS,

Can you explain the steps please?

[soseducation]

Distance equal to speed x time.

so students are required to form an equation, judging from the fact that the distance between P and Q remains the same. Let the time taken travelled using the speed 40km/h be T.

70 (T-6) = 40 x T

From there, you can find the value of T.

It is quite tedious for primary school kids to attempt this question. Sadly this is the kind of question that has been appearing in examinations

[belnanna]

Distance equal to speed x time.

so students are required to form an equation, judging from the fact that the distance between P and Q remains the same. Let the time taken travelled using the speed 40km/h be T.

70 (T-6) = 40 x T

From there, you can find the value of T.

It is quite tedious for primary school kids to attempt this question. Sadly this is the kind of question that has been appearing in examinations

Can you please explain how do u get 560 ?

THe answer given was explained in another way:
x/40 = x/70 +6
7x= 4x +1680
3x = 1680
1x = 1680/3 = 560 km.. (Still dont understand how to get 1680 from this answer)

[soseducation]

It is same method but they use an alternate way. T +6 is because T represent the time taken to travel at 70km/h, so the time taken by 40km/h will be longer.


My method:

Let T be the time taken to travel at 40 km/h
70 (T-6) = 40 x T

70T - 420 = 40 T

30 T = 420

T = 14.

So Distance = speed x time
40 x 14 = 560

[iwork]

Can someone please advise on this question? Dont really understand how to solve. ><
Thank you so much in advance!

Mr Teo traveled at 40km/h from town P to town Q. If he increases his speed by 30km/h ,he will take 6 hours lesser to reach his destination.
What was the distance between town P and town Q?

This is a distance-speed problem that can be solved without algebra. It could be solved by simply understanding the problem and worked from another angle. (In fact, it was trained in Heuristic Maths or Maths Olympiad program which I had taught in schools.)

You have to realize few points
1. the speed increase by 30km/h
2. the time taken reduced by 6 hours.

point 2 => the extra 6 hours will cut the travel distance by 6 x 40 =240km

point 1 => this distance will have to covered by the extra speed of 30km/h in 240/30 = 8 hours.

So the distance between the 2 towns will be 70km/h x 8 h = 560km.

[soseducation]

Can someone please advise on this question? Dont really understand how to solve. ><
Thank you so much in advance!

Mr Teo traveled at 40km/h from town P to town Q. If he increases his speed by 30km/h ,he will take 6 hours lesser to reach his destination.
What was the distance between town P and town Q?

This is a distance-speed problem that can be solved without algebra. It could be solved by simply understanding the problem and worked from another angle. (In fact, it was trained in Heuristic Maths or Maths Olympiad program which I had taught in schools.)

You have to realize few points
1. the speed increase by 30km/h
2. the time taken reduced by 6 hours.

point 2 => the extra 6 hours will cut the travel distance by 6 x 40 =240km

point 1 => this distance will have to covered by the extra speed of 30km/h in 240/30 = 8 hours.

So the distance between the 2 towns will be 70km/h x 8 h = 560km.

but i know schools are teaching it using the algebra method

[Laurel111]

Can someone please help with this question? Thank you.

[soseducation]

http://tinypic.com/r/9zu139/8

Hi, you can draw remainder model since it is only for 3 shops, then work backwards.

Double check:

1. 140/2 = 70 70-10 = 60

2. 60/2 = 30 30 - 10 = 20

3. 20/2 = 10 10-10=0 (no money left)

[Laurel111]

http://tinypic.com/r/9zu139/8

Hi, you can draw remainder model since it is only for 3 shops, then work backwards.

Double check:

1. 140/2 = 70 70-10 = 60

2. 60/2 = 30 30 - 10 = 20

3. 20/2 = 10 10-10=0 (no money left)

Thanks for the model. I see it now.