Q&A - PSLE Math

[Nebbermind]

underthesea:

How many pupils took part in all three CIP activities?

Boy! I as confused by this sentence too!!

[underthesea]

small:

1000 pupils took part in all three CIP activities

I thought the question asking how many pupils took parts in all three CIP activities? Not the total number of pupils took parts in the CIP.

Nebbermind:

underthesea:

How many pupils took part in all three CIP activities?

Boy! I as confused by this sentence too!!

Yes, I am confused too.

[genevieve08]

Seashore --1/4 = 5/20

Remainder – 1 - 5/20 = 15/20
Charity-- 3/5 x 15/20 = 9/20
9/20+5/20=14/20
Recycle-- 1-14/20=6/20

5x6=30
9x5=45
6x4=24

30+45+24=99


4950/99=50
50x5=250
50x9=450
50x6=300

300+450+250=1000


There are 1000 pupils.

[alng]

Hi, please help to solve the question below. TIA!


Jane had some rubber bands. 60% of her rubber bands were yellow and the rest were red. She kept 41 yellow rubber bands and 31 red rubber bands and gave the rest to Sam. Sam divided the rubber bands into group of 8. In each group of 8 rubber bands, there were 5 yellow rubber bands. How many rubber bands did Jane have at first?

[alng]

alng:

Hi, please help to solve the question below. TIA!


Jane had some rubber bands. 60% of her rubber bands were yellow and the rest were red. She kept 41 yellow rubber bands and 31 red rubber bands and gave the rest to Sam. Sam divided the rubber bands into group of 8. In each group of 8 rubber bands, there were 5 yellow rubber bands. How many rubber bands did Jane have at first?

I manage to solve this qn by using trial and error. Is this the only method? Thanks!

[speedmaths.012624com]

alng:

alng:

Hi, please help to solve the question below. TIA!


Jane had some rubber bands. 60% of her rubber bands were yellow and the rest were red. She kept 41 yellow rubber bands and 31 red rubber bands and gave the rest to Sam. Sam divided the rubber bands into group of 8. In each group of 8 rubber bands, there were 5 yellow rubber bands. How many rubber bands did Jane have at first?

I manage to solve this qn by using trial and error. Is this the only method? Thanks!

Hi,

You may use the Bags and Boxes Method to solve ALL the Double-Ratios problems for PSLE Maths:
(The Bags and Boxes Method can be found in the book: Raffles Maths Tricks - Volume 1; first printed in 2006.)

Let’s say that:
Jane had 3 Bags of Yellow rubber bands and 2 Bags of Red rubber bands.
(The number of rubber bands in each of the 5 Bags is the same)
She kept 41 Yellow rubber bands and 31 Red rubber bands and gave the rest to Sam.
Sam put the Yellow rubber bands in 5 Boxes, and the Red rubber bands in 3 Boxes.
(The number of rubber bands in each of the 8 Boxes is the same)

Yellow:
3 Bags – 41 → 5 Boxes
(x3)
9 Bags – 123 → 15 Boxes

Red:
2 Bags – 31 → 3 Boxes
(x5)
10 Bags – 155 → 15 Boxes

10 Bags – 155 → 15 Boxes → 9 Bags – 123
10 Bags – 155 → 9 Bags – 123
10 Bags – 155 + 155 → 9 Bags – 123 + 155
10 Bags → 9 Bags + 32
1 Bag → 32 (rubber bands)

At first, Jane had 5 Bags, or 5 x 32 = 160 rubber bands.

Cheers

Speed Maths Centre
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=43&t=25433&start=10

[alng]

speedmaths.com:

Hi,

You may use the Bags and Boxes Method to solve ALL the Double-Ratios problems for PSLE Maths:
(The Bags and Boxes Method can be found in the book: Raffles Maths Tricks - Volume 1; first printed in 2006.)

Thanks very much! I have come across this method before but never realise it is for Double Ratio problems. In fact, never encounter this term before. Thanks!

[Winx5015]

Hi,


Pse help me with the following questions!

(1). Kelly and Susan had some money each. If Kelly spent 4100 each day and Susan spent $50 each day, Kelly will still have $500 left when Susan had spent all her money. If Kelly spent $50 each day and Susan spent $100 each day, Kelly will still have $2300 left when Susan had spent all her money. How much did each of them have?

(2). Stefane and Lee Ling have some money. If Stefane gives Lee Ling $4.50, the two girls will have an equal amount of money. If Lee Ling gives $4.50 to Stefane, Stefane will have twice as much as Lee Ling. How much money do the 2 girls have altogether?

Thanks!

[kamom]

Given that one and only one of the following statements is correct, which one is correct?


1)All the statements below are correct
2)None of the statements below is correct
3)One of the statements above is correct
4)All of the statements above is correct
5)None of the statements above is correct

Ans is (5), can someone explain to me :idea:

THANKS A MIL

[Nebbermind]

Winx5015:

If Kelly spent 4100 each day and Susan spent $50 each day....,

do u mean $100?