Q&A - PSLE Math

[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:

[kiasuaunt]

Hi - pls help me with the md for this q:


Ben n Mary went shopping with a total of $204. Ben had $12 more than Mary. Mary spent 4 times as much money as Ben and was left with half the amount of money that Ben had left.

a) How much money did Ben bring along for shopping?

b) How much money had Ben left after shopping?

Thank you.

[speedmaths.012624com]

kiasuaunt:

Hi - pls help me with the md for this q:


Ben n Mary went shopping with a total of $204. Ben had $12 more than Mary. Mary spent 4 times as much money as Ben and was left with half the amount of money that Ben had left.

a) How much money did Ben bring along for shopping?

b) How much money had Ben left after shopping?

Thank you.

Hi,

One possible Solution to Part (a)

Ben n Mary went shopping with a total of $204
Sum = $204

Ben had $12 more than Mary
Difference = $12

Bigger number = (Sum + Difference) ÷ 2
Sam → ($204 + $12) ÷ 2 = $108

Hope this helps.

Cheers

speedmaths.com


PS:
Smaller number = (Sum - Difference) ÷ 2
Mary → ($204 - $12) ÷ 2 = $96

-

[speedmaths.012624com]

kiasuaunt:

Hi - pls help me with the md for this q:


Ben n Mary went shopping with a total of $204. Ben had $12 more than Mary. Mary spent 4 times as much money as Ben and was left with half the amount of money that Ben had left.

a) How much money did Ben bring along for shopping?

b) How much money had Ben left after shopping?

Thank you.

Hi,

One possible Solution to Part (b)
Using the Advanced Model Method
(or Bags and Boxes Method)

Sam → ($204 + $12) ÷ 2 = $108
Mary → ($204 - $12) ÷ 2 = $96

Let Sam put his $108 into 1 Bag and 2 Boxes.
Let Mary put her $96 into 4 Bags and 1 Box.

(Each of the 5 Bags contains the same amount of money.)
(Each of the 3 Boxes contains the same amount of money.)

Mary spent 4 times as much money as Ben.
Mary spent her 4 Bags of money, and Ben spent his 1 Bag of money.

Mary was left with half the amount of money that Ben had left.
Mary had 1 Box of money left, and Ben had 2 Boxes of money left.

Mary:
$96 → 4 Bags + 1 Box…………….(Row 1)

Sam:
$108 → 1 Bag + 2 Boxes
(x 4)
$432 → 4 Bags + 8 Boxes…………(Row 2)

Row 2 – Row 1
$432 - $96 → $336 → 0 Bag + 7 Boxes
7 Boxes → $336
1 Box → $48
2 Boxes → $96

Ben had 2 Boxes of money left.
Ben had $96 left.

Hope this helps.

Cheers

speedmaths.com

PS.
Parents who wish to know more about the Advanced Model Method can check out our thread in the Happenings forum.

.

[2DMommy]

2DMommy:

Please help me with these two questions :


1) Pasqual, Quincy , Robert and Sheridan had a total of 242 muffins. Each of them would have an equal number of muffins if Pasqual bought 10 more muffins, Quincy gave away 21 muffins, Robert increased the number of muffins he had by 2/3 and Sheridan decreased the number of muffins he had by 20%. How many muffins did each of them have ?

2) 0.6 of Luqman's allowance is twice as much as 10% of Zachary's allowance. After Luqman's spends thrice as much as Zachary, Luqman's and Zachary left with $36 and $252 respectively. How much does Zachary and Luqman's each have at first?

Thank you.

Can someone please help me with the above two questions? Thank you !

[nounou]

:rahrah: :thankyou: :udaman: :goodpost: :lovesite:

:thankyou: :thankyou:

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.

[nounou]

Selamat Hari Raya :rahrah:

Please help to solve this Q: :imconstipated: :?: :gloomy:
How I love the smilies :rotflmao:

Roy left Point A for Point B, cycling at 8km/h. 1 hour later, Patrick, also heading for Point B, passed Point A cycling at a uniform speed. He caught up with Roy when he was 14 km away from Point B. How long did Patrick take to cycle from Point A to Point B which was 54km apart?
:thankyou: :thankyou: :thankyou:

[Robertpattinsonidle]

Please help me. how to solve these types of qsns? http://i47.tinypic.com/65v0aw.jpg\">

[MathIzzzFun]

2DMommy:

Please help me with these two questions :


1) Pasqual, Quincy , Robert and Sheridan had a total of 242 muffins. Each of them would have an equal number of muffins if Pasqual bought 10 more muffins, Quincy gave away 21 muffins, Robert increased the number of muffins he had by 2/3 and Sheridan decreased the number of muffins he had by 20%. How many muffins did each of them have ?

2) 0.6 of Luqman's allowance is twice as much as 10% of Zachary's allowance. After Luqman's spends thrice as much as Zachary, Luqman's and Zachary left with $36 and $252 respectively. How much does Zachary and Luqman's each have at first?

Thank you.

Can someone please help me with the above two questions? Thank you !

Both questions could be solved quite easily with MD, I shall use the units approach due to time constraint.

Q1.
In the end, each will have 20u
At first,
P --> 20u -10
Q --> 20u + 21
R --> 12u
S --> 25u
Total --> 77u + 11 = 242
1u --> 33

At first, number of muffins each had :
P --> 650
Q --> 681
R --> 396
S --> 825

cheers.

[MathIzzzFun]

2DMommy:

Please help me with these two questions :



2) 0.6 of Luqman's allowance is twice as much as 10% of Zachary's allowance. After Luqman's spends thrice as much as Zachary, Luqman's and Zachary left with $36 and $252 respectively. How much does Zachary and Luqman's each have at first?

Thank you.

Can someone please help me with the above two questions? Thank you !

3/5 Luq's allowance = 2/10 Zac's allowance
3/5 Luq's allowance = 3/15 Zac's allowance
Luq's allowance : Zac's allowance --> 1 : 3

Luq's spending : Zac's spending --> 3u : 1u
Luq's allowance : Zac's allowance --> 3u + $36 : 1u + $252 = 1 : 3

So, 9u + $108 = 1u + $252
1u --> 18

Luq's allowance --> $90
Zac's allowance --> $270

cheers.