Q&A - PSLE Math

[corneyAmber]

Please click the link below for the solution using model diagrams:


http://i3.photobucket.com/albums/y74/miamia2004/P5Math20081014.jpg

[cutemum]

How about this one, This is from oldschool test papers P5 math 2008


Four boys, Alex, Bryan, Calvin and Derrick, each have some stamps. The number of stamps Alex has is 1/2​ of the total number of stamps Bryan, Calvin and Derrick have. The number of stamps Bryan has is 1/3​ of the total number of stamps Alex, Calvin and Derrick have. The number of stamps Calvin has is 1/4​ of the total number of stamps Alex, Bryan and Derrick have. If Derrick has 78 stamps, find the total number of stamps Alex and Bryan have altogether.

The answer is 210

[lizawa]

cutemum:

How about this one, This is from oldschool test papers P5 math 2008


Four boys, Alex, Bryan, Calvin and Derrick, each have some stamps. The number of stamps Alex has is 1/2​ of the total number of stamps Bryan, Calvin and Derrick have. The number of stamps Bryan has is 1/3​ of the total number of stamps Alex, Calvin and Derrick have. The number of stamps Calvin has is 1/4​ of the total number of stamps Alex, Bryan and Derrick have. If Derrick has 78 stamps, find the total number of stamps Alex and Bryan have altogether.

The answer is 210

You can use ratio to solve this question.

A : B+C+D
= 1: 2
= 20: 40

B: A+C+D
= 1:3
= 15:45

A+B+D
=1:4
=12:48

First step is to make all the \"total units\" equal. So the common multiple of 3 (1+2), 4 (1+3) and 5 (1+4) is 60.

A+B = 20+15 = 35 units.
From A+B+D = 12:48
D = 48 - 35 = 13 units.

Since D has 78 stamps,
13 units = 78
1 unit = 6 stamps

A+B = 35 units = 35 *6 = 210 stamps.

[heutistmeintag]

ks2me:

Please click the link below for the solution using model diagrams:

http://i3.photobucket.com/albums/y74/miamia2004/P5Math20081014.jpg

I always get brain damage trying to figure out models. :oops:

lizawa:

...
First step is to make all the \"total units\" equal. So the common multiple of 3 (1+2), 4 (1+3) and 5 (1+4) is 60.
...

That's the missing link I was looking for. Thanks for the enlightenment, lizawa. *clap*clap*clap*

[lizawa]

heutistmeintag:

That's the missing link I was looking for. Thanks for the enlightenment, lizawa. *clap*clap*clap*

You are welcome. The most difficult part is always to identify the relationship among all the given numbers. Once you get that, the rest is a breeze.

[cutemum]

Thanks lizawa...:)

[clover18]

Hi


I’m really impressed with the fact that so many parents make attempts to coach the kids and solve the problems themselves. By the way, I was recently recommended assessment books by Simon Eio. Was told its very well structured. Anyone has feedback on Andrew er’s tuition centre which he started recent years? Would you recommend it? What abt Learning Lab Math program?

[suiyuan]

Thank you for your time.


1) Tom’s monthly allowance is $42 more than Eric’s. Eric spends $54 more than Tom every month. Eric’s savings is 1/2 of Tom’s savings. If Tom spends 3/7 of his allowance every month, what is his allowance for the entire year?

2) Siti paid $8.56 for some 26-cents, 30-cents and 50-cent stamps. She bought 4 more 30-cents stamps than 50-cent stamps. There were twice as many 26-cent stamps as 30-cent stamps. How many 26-cent stamps did she buy?

3) Terry walks to school at an average speed of 4km/h every day. One day, after walking a distance of 1km, he realised that his watch was slow. So, he ran at a constant speed and managed to reach the school just on time. Later, he calculated that if he had run at this speed right from the start of the journey, he would have reached school 5 minutes earlier. What was his running speed?

[Vanilla Cake]

Hi suiyuan,

Are these P5 or P6 qns ?

A1 : $ 4032 (Tom's allowance for the entire year)
A2 : 16 each of 26-cent stamps
A3 : 6 km/h (Terry's running speed)

Pls confirm if my answers are correct ?

[suiyuan]

Vanilla Cake:

Hi suiyuan,

Are these P5 or P6 qns ?

A1 : $ 4032 (Tom's allowance for the entire year)
A2 : 16 each of 26-cent stamps
A3 : 6 km/h (Terry's running speed)

Pls confirm if my answers are correct ?

Hi Vanilla Cake

Thank you for your reply.
P6 questions
No answers were given for Q1 and 2
As for Q3, you are correct.

Please share your detailed solutions for these questions.