Tutor MathsGuru: Ask me for your burning Maths questions!

[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.

[sachiko]

MOE Hater:

sachiko:

Hi MahtsGuru


I would appreciate if you could help me with the following qns:

3 tins, A, B and C, contained a total of 240 cookies. Some cookies from A were transferred to B and the number of cookies in B was doubled. Then some cookies from B were transferred to C and the number of cookies in C was doubled. As a result of this, there was an equal number of cookies in each tin. How many cookies were in each tin at first?

TIA.

Sachiko

As the exchange of cookies took place between the 3 tins, the total number of cookies would always be 240. As the no. of cookies in each tin in the end were the same, we can calulate the no. of cookies in each tin in the end.

The no. of cookies in each tin in the end = 240/3 = 80

As the no of cookies in Tin C were doubled before it became 80, we can calculate the no. of cookies in Tin C at first. From this, we can also tabulate the no. of cookies in tin B before the original no. was doubled.

Cookies added to Tin C = Cookies in tin C at first = 80/2 = 40

Cookies in Tin B after original no. doubled = 80 + 40 = 120

It is plain sailing from here. We can calculate the original no. of cookies in Tin B, and with the total no. of cookies and the original no of cookies in each Tin B and C, we can calculate the no. of cookies orginally in Tin A.

Cookies in Tin B at first = 120/2 = 60

Cookies in Tin A at first = 240 - 40 - 60 = 140

Alternatively, we can see that the no. of cookies in tin B at first is also the no. of cookies removed from Tin A. We also know the no. of cookies left in Tin A, so by adding both values we can derive the no. of cookies in Tin A at first

Cookies in Tin A at first = 80 + 60 = 140

Hope you can understand my rather wordy solution. Algebra can be used but to some children it is quite confusing.

Thanks MOE Hater.

[Almighty]

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

Thank you very much dharma

[tiger262]

Can anyone kindly put up a solution for this question:


Cars are travelling to and fro from Greens Town to Sins City. The cars leave the Towns at regular interval and a car will meet another car coming in the opposite direction at every 6 min. Ronald starts cycling from Greens Town to Sins City while Annie starts cycling in the opposite direction. Both leave the Towns at the same time. Ronald and Annie will meet a car coming in the opposite direction every 7 and 8 min respectively. They met each other after cycling for 56 min. What is the time taken by a car to travel from Greens City to Sins City?

Thank you very much.