Tutor MathsGuru: Ask me for your burning Maths questions!

[tianzhu]

Almighty:

2) David and Michael drove from Town A to Town B at different speeds. Both didnot change their speeds throughout their journeys.
David started his journey 30 minutes earlier than David. When Michael reached Town B 50 minutes earlier than David, David had travelled 4/5 of the journey and was 75 Km away from Town B.a) What was the distance between Town A and Town B?
b) How many Kilometres did David travel in 1 hour?
c) What was the time taken by Michael to travel from Town A to Town B?

Hi

You may want to take a look at the underlined sentence. Is there a typo error?

Best wishes

[dolphinsiah]

Good Afternoon MathsGuru,


Please help to solve below P5 Maths:

There were 4 times as many chairs as tables in a store room. After 67 chairs and 8 tables were taken away, there were twice as many tables and chairs left in the store room.
How may tables were there in the store room at first.

Thanks in advance :lol:

[kwcllf]

ruyu:

Vanilla Cake:

[quote=\"ruyu\"]dont understand :? care to explain?

Thks for pointing out, I have amended the workings.
Average speed should be 3 km/h

LCM of 2 and 6 is 12

Time taken to climb uphill @ 2 km/h = 12/2 = 6h
Time taken to go downhill @ 6 km/h = 12/6 = 2h
Total time taken = 8h
Total distance covered = 12x2 = 24 km
Average speed for the entire trip = 24km/8h = 3 km/h

no seriously i dont understand[/quote]How about the following explanation:

Downhill = 6km/h
In other words, 1h = travels 6km


Uphill (2km/h): To travel 6km, time taken = 3h
Downhill: To travel 6km, time taken = 1h
Total Distance travelled = 6km+6km = 12km
Total Time taken = 3h+1h = 4h

Therefore, Average speed = 12km/4h = 3km/h

[Dharma]

Almighty:

2) David and Michael drove from Town A to Town B at different speeds. Both didnot change their speeds throughout their journeys.
David started his journey 30 minutes earlier than Michael. When Michael reached Town B 50 minutes earlier than David, David had travelled 4/5 of the journey and was 75 Km away from Town B.a) What was the distance between Town A and Town B?
b) How many Kilometres did David travel in 1 hour?
c) What was the time taken by Michael to travel from Town A to Town B?

a)\t1/5 of journey => 75km
\tDistance from Town A to Town B = 5 X 75km = 375km

b)\tDavid needs 5/6 hours to complete his last 75km
\t5/6 hrs => 75km
\t1 hr => 90km
\tDavid travels 90km in 1 hr

c)\tTime taken by David from Town A to Town B = 375km/ 90km/h = 4 hrs 10 mins
\tTime taken by Michael from Town A to Town B is 80 mins faster than 4 hrs 10 mins.
\t= 2 hrs 50 mins

[Muffins]

dolphinsiah:

Good Afternoon MathsGuru,


Please help to solve below P5 Maths:

There were 4 times as many chairs as tables in a store room. After 67 chairs and 8 tables were taken away, there were twice as many tables and chairs left in the store room.
How may tables were there in the store room at first.

Thanks in advance :lol:

At the beginning, there was 1 unit of tables and 4 units of chairs
So:

T : C
1 : 4
(-8 ) (-67)
2 : 1

Using cross-multiplication, (multiplying the opposite result below by the original result on top):

1 unit - 8 = 8u - 134

Adding the negatives back gives you:

1 unit = 8 units - 126

7 units = 126

1 unit = 18

Hope I helped!

[corneyAmber]

Picture Solution:


http://i724.photobucket.com/albums/ww246/ks2me/P5Mathtableschairs.jpg\">

[Almighty]

Thankyou tianzhu 4 spoting out the unrectified typo error. I edited it after reading yr msg. Just give me a day or two to get back my HWassessment paper which i had submitted 2 my teacher.I'll recheck the whole problem again after receiving it. My apologies 2 all 4 having wasted yr time. :?

[dolphinsiah]

Muffins:

dolphinsiah:

Good Afternoon MathsGuru,


Please help to solve below P5 Maths:

There were 4 times as many chairs as tables in a store room. After 67 chairs and 8 tables were taken away, there were twice as many tables and chairs left in the store room.
How may tables were there in the store room at first.

Thanks in advance :lol:

At the beginning, there was 1 unit of tables and 4 units of chairs
So:

T : C
1 : 4
(-8 ) (-67)
2 : 1

Using cross-multiplication, (multiplying the opposite result below by the original result on top):

1 unit - 8 = 8u - 134

Adding the negatives back gives you:

1 unit = 8 units - 126

7 units = 126

1 unit = 18

Hope I helped!

Good morning Muffins,

Yes, the answer is correct.
But I have 1 question on the 2nd step...the cross multiplication is it acceptable in PSLE?

For your kind advise,please. :?:

Thanks

[dolphinsiah]

ksi:

Picture Solution:


http://i724.photobucket.com/albums/ww246/ks2me/P5Mathtableschairs.jpg\">

Good morning KSI,

Your method was how my child school teacher taught...but my child finds it very difficult to understand...
:?

[corneyAmber]

4 times as many => 4 green solid blocks (chairs)

table = 1 time of chair => 1 solid purple block (tables)
Then the perforated blocks are taking away 67 chairs and 8 tables which I placed outside for clarity
==> tables become 2 times of chair hence the u and 2u in the diagram,
the trick in model diagram is to identify what is "u". In order to draw the 2u for tables, you have to imagine the ‘8’ part is removed and then just halved the remaining block to form the 2u.

So now from the diagram, you can see that each solid green block = 2u+8
Then the equations can be formed to solve "u".

Maybe you can share with me which part he does not understand.