Q&A - PSLE Math

[Chan09]

Need help on these; thank you


1) team A and team B sent pupils in groups of 10, for a ball game. If the 2 teams used mini vans that have a seating capacity of 14 passengers, they will need 72 vans. If they use mini vans that have a seating capacity of 19, team B will need 7 more vans than team A. If the 2 teams do not share a van and each van is pack to a max of 19 for team B, how many more pupils are there in team B than team A?
Ans: 140

2) There are 98 teachers and each female teacher has 8 notepads and each male teacher has 3 notepads given to them. The male teachers received 355 notepads less than the female teachers. How many female teachers are there?
Ans: 59, for this question I applied the excess and shortage concept though I understand that this is incorrect as it is suppose to make a supposition. Plse help.

[MathIzzzFun]

Treelodge:

Can some please help to do this Q? :imdrowning:

:thankyou: :thankyou:

Car A and Car B left Town Y at the same time, heading in the opposite direction. Car A headed for Town Z while CAr B left for Town X. The speed of Car B was 20km/h faster than Car A. After 1/2 h, Car A had completed 2/3 of its journey while Car B had completed 1/2 of its journey. The two cars were also 110km apart.
a) Calculate the speed of Car A
b) How far was Car B from Town X when Car A reached its destination?
:?: :thankyou:

after 1/2h, 20km x 1/2 =10 km --> Car B would have travelled 10 km more than Car A.
Distance travelled by A --> 1 unit
Distance travelled by B --> 1 unit + 10 (1/2 journey)
Total 2 units + 10 --> 110
1 unit --> 50 km
A's speed = 50 km ÷ 1/2 = 100 km/h

Fraction of journey travelled by A : B
= 2/3 : 1/2
= 1 : 3/4
When A reached its destination, B would have travelled 3/4 of its journey ie it will still have 1/4 of the journey to travel
1/2 journey --> 1 unit + 10 = 60 km
1/4 journey --> 30 km

Car B will be 30 km from X.

cheers.

[mumworks]

Thanks Speedmaths.com and MathIzzzFun for helping to answer my earlier questions.


Can anyone help on this Qs ?

1/2 of a rectangle overlaps with 1/3 of a circle. What fraction of the figure is overlapped ?

Thank you very much.

[fightingmom]

Hi,


Please help with the following question :

At 7am, Car A left Town X for Town Y while Car B left Town Y for Town X. At 3pm, the two cars passed each other. 5 hours later, Car A reached Town Y but Car B was still 150km away from Town X. Find the distance between Town X and Town Y.

TIA!

[MathIzzzFun]

mumworks:

Thanks Speedmaths.com and MathIzzzFun for helping to answer my earlier questions.


Can anyone help on this Qs ?

1/2 of a rectangle overlaps with 1/3 of a circle. What fraction of the figure is overlapped ?

Thank you very much.

1/2 rectangle = 1/3 circle
rectangle --> 2 units
circle --> 3 units
overlapped --> 1 unit

can you continue from here ?

cheers.

[jarenchuatw]

Got another question to to ask - see attached, but ignore the writing in blue (coz I m not sure whether it is correct or not)

[MathIzzzFun]

fightingmom:

Hi,


Please help with the following question :

At 7am, Car A left Town X for Town Y while Car B left Town Y for Town X. At 3pm, the two cars passed each other. 5 hours later, Car A reached Town Y but Car B was still 150km away from Town X. Find the distance between Town X and Town Y.

TIA!

concept of combined speed

When Car A and Car B meet, the total distance covered is XY and the total time taken is 8 hours (7am to 3pm).

5 hours after passing each other, remaining distance to be covered = 150 km

Both cars took 3 hours (8-5) to cover a total distance of 150 km,
combined speed --> 150 km/3h = 50km/h (quite a slow speed considering that this is a combined speed)
Total distance between XY = 50 km/h x 8h = 400 km

cheers.

[MathIzzzFun]

Chan09:

Need help on these; thank you


2) There are 98 teachers and each female teacher has 8 notepads and each male teacher has 3 notepads given to them. The male teachers received 355 notepads less than the female teachers. How many female teachers are there?
Ans: 59, for this question I applied the excess and shortage concept though I understand that this is incorrect as it is suppose to make a supposition. Plse help.

similar questions using area model --> which is supposition method using MD

http://www.flickr.com/photos/62167097@N02/6963704884/in/set-72157629901522689/

http://www.flickr.com/photos/62167097@N02/6808896113/in/set-72157629901522689

http://www.flickr.com/photos/62167097@N02/6879749576/in/photostream

http://www.flickr.com/photos/62167097@N02/7634466300/in/set-72157629901522689



cheers.

[MathIzzzFun]

Chan09:

Need help on these; thank you


1) team A and team B sent pupils in groups of 10, for a ball game. If the 2 teams used mini vans that have a seating capacity of 14 passengers, they will need 72 vans. If they use mini vans that have a seating capacity of 19, team B will need 7 more vans than team A. If the 2 teams do not share a van and each van is pack to a max of 19 for team B, how many more pupils are there in team B than team A?
Ans: 140

I will provide some pointers for Q1

Total number of pupils is a multiple of 10 since both teams sent pupils in groups of 10.
So, 72 vans with seating capacity of 14 passengers --> what is the total number if all vans are full ? What is the number of pupils ?

Once the number of pupils is determined, how many vans with seating capacity of 19 is needed to accomodate all ?

cheers.

[fightingmom]

MathIzzzFun:

fightingmom:

Hi,


Please help with the following question :

At 7am, Car A left Town X for Town Y while Car B left Town Y for Town X. At 3pm, the two cars passed each other. 5 hours later, Car A reached Town Y but Car B was still 150km away from Town X. Find the distance between Town X and Town Y.

TIA!

concept of combined speed

When Car A and Car B meet, the total distance covered is XY and the total time taken is 8 hours (7am to 3pm).

5 hours after passing each other, remaining distance to be covered = 150 km

Both cars took 3 hours (8-5) to cover a total distance of 150 km,
combined speed --> 150 km/3h = 50km/h (quite a slow speed considering that this is a combined speed)
Total distance between XY = 50 km/h x 8h = 400 km

cheers.

This is the first time I came across \"combined speed\".

:thankyou: so much for your help ! :salute: