Q&A - PSLE Math

[happyluckymom]

Can someone help me solve Rosyth 2008 prelim maths paper last question number 47?

[kitty2]

singmathstutor:

kitty2:

Please help with this question,Thanks


A group of pupils sat for 2 tests,test A & test B.The number of pupils who failed test A was 1/7 of those who passed test A.

a) Given that there were 20 pupils who fialed test A,how many pupils passed test A?

b) The number of pupils who failed test B was 1/4 of those who failed test A.What fraction of the pupils passed test B?

a) Fail: 1u, Pass: 7u
1u-->20
7u-->7x20=140
140 pupils passed test A (ans)

b) 1/4x20=5
5 pupils failed test B
total number of pupils = 20+140=160 (from part a)
number of pupils who passed test B = 160-5=155
fraction of pupils who passed test B = 155/160 = 31/32 (ans)

:thankyou:

[singmathstutor]

kitty2:

singmathstutor:

[quote=\"kitty2\"]Please help with this question,Thanks


A group of pupils sat for 2 tests,test A & test B.The number of pupils who failed test A was 1/7 of those who passed test A.

a) Given that there were 20 pupils who fialed test A,how many pupils passed test A?

b) The number of pupils who failed test B was 1/4 of those who failed test A.What fraction of the pupils passed test B?

a) Fail: 1u, Pass: 7u
1u-->20
7u-->7x20=140
140 pupils passed test A (ans)

b) 1/4x20=5
5 pupils failed test B
total number of pupils = 20+140=160 (from part a)
number of pupils who passed test B = 160-5=155
fraction of pupils who passed test B = 155/160 = 31/32 (ans)

:thankyou:[/quote]You're welcome, kitty

[Muffins]

Got a question for you guys to answer. It's from a primary school test paper. I need the working in models, if you don't mind...


In a conference, there were some men and women. In the first day, there were 80 less women than men. In the second day, the number of men who came decreased by 10%, and the number of women who had arrived increased by 20%. The total number of people who had arrived for the second day was 1542.

How many men and women were there for the first and second day?

TIA.

[Maths Monster]

Muffins:

Got a question for you guys to answer. It's from a primary school test paper. I need the working in models, if you don't mind...


In a conference, there were some men and women. In the first day, there were 80 less women than men. In the second day, the number of men who came decreased by 10%, and the number of women who had arrived increased by 20%. The total number of people who had arrived for the second day was 1542.

How many men and women were there for the first and second day?

TIA.

Using Model:

Let 10u be the number of women on day 1

Day 1:
M [10u] [80]
W [10u]

Day 2: In the second day, the number of men who came decreased by 10%, and the number of women who had arrived increased by 20%.
M [9u] [72]
W [12u]

The total number of people who had arrived for the second day was 1542. We can write:
9u + 72 + 12u = 1542
u = 70


On Day 1, there were 780 men and 700 women.
On Day 2, there were 702 men and 840 women.

Check:
Day 1 to Day 2:
Men 780 to 702 => 10% decrease
Women 700 to 840 => 20% increase
Total came on Day 2 = 702 + 840 = 1542

[tianzhu]

Hi muffins

Hope this helps.

http://farm5.static.flickr.com/4111/4841740107_0767d9d0cb_b.jpg\">

Best wishes

[Muffins]

tianzhu:

Hi muffins

Hope this helps.

http://farm5.static.flickr.com/4111/4841740107_0767d9d0cb_b.jpg\">

Best wishes

Thank you SO much Tianzhu. This is a lifesaver! :thankyou:

[tianzhu]

Hi Muffins


You’re welcome.

Best wishes

[tianzhu]

Hi


Under the topic of Speed, Time and Distance, P6 students learnt about the formula, Distance =Speed*Time. It’s important to understand the concepts behind the formula rather than applying it without much understanding.

There are many variations in questions on Speed, thus, sometimes students may find them challenging.

One common type of question is overtaking or catching up. In this type of question, two vehicles or travellers leave the same point in the same direction but starting at different times. They have different speed. The vehicle/traveller that started later is faster.

Since this is an 'overtaking/catching up' problem, we should take note that the distance covered by both vehicles/travellers is the same at the time of overtaking/catching up.

In this post, I’ll share two ways to solve such problems. Hope you’ll find them useful.

Two similar types of questions

Q1) A lorry travelled at an average speed of 72km/h from Pink Town to Happy Town. 50 minutes later, a van started out from the same point towards the same destination at an average speed of 90km/h, reaching Happy Town at the same time.
a. How long did the van take to travel from Pink Town to Happy Town?
b. If both the lorry and the van arrived at Happy Town at 4.05pm at what time did the lorry start out?

Q2) Mary and Ken travelled from Town A to Town B. Mary left Town A at 0915 and took 4h to reach Town B. Ken left Town A at 1000 and took 2h 45min to reach Town B. At what time did Ken pass Mary?

Best wishes

http://farm5.static.flickr.com/4154/4848538438_172dcb6de9_b.jpg\">

http://farm5.static.flickr.com/4149/4847914819_b35953e42b_b.jpg\">

http://farm5.static.flickr.com/4107/4848566704_51dbb6f1e2_b.jpg\">

[Muffins]

hi Tianzhu, just wanted to ask, who is that person in your model workings? Your DD?