Q&A - PSLE Math

[atutor2001]

stary:

Hi all,


Can someone explain/show me the workings of this question?

http://www.flickr.com/photos/64113082@N03/6007585363/in/photostream
Ans: 5
(SCGS Prelim 2010 P6 Question 3)

Thanks!

Add the numbers at the 4 corners and divide by 4. (the middle number is the average)

[MathIzzzFun]

stary:

Hi all,


Can someone explain/show me the workings of this question?

http://www.flickr.com/photos/64113082@N03/6007585363/in/photostream
Ans: 5
(SCGS Prelim 2010 P6 Question 3)

Thanks!

Hi

sum of corners = 4 x centre

cheers.

[Angel25]

Hi, Can someone help me with this Remainder Concept Qn.


Wiki had some beads. He gave 2/5 of them to his brother. 1/3 of the remaining beads were shared among his three friends. if each friend received 45 lesser than the amount received by Wiki’s brother, how many beads did Wiki have at first??

[chrisu]

Thank you very much.

MathIzzzFun:

chrisu:

Pls help to solve;

Complete the number pattern.
1, 2, 10, 37, 101, _____
(1) 138
(2) 158
(3) 226
(4) 246

Thanks.

Hi

1 (+1^3) 2 (+2^3) 10 (+3^3) 37 (+4^3) 101 (+5^3) 226

cheers.

[Angel25]

Beatrice arranged some beads in 15 short rows and 14 long rows. there were 36 more beads in each long row than each short row. Beatrice used 70% of the beads to arrange in long rows while the rest of the beads were arranged in short rows. How many beads were there in each short row?


steps and explanations pls

[Jazpy]

CASE CLOSED............ Ive found the ans :rahrah:


ANS:176

Qn: At first, Kumar had only $5-notes and Devi had only $2-notes. The number of notes Kumar had is 2/3 of Devi's notes. When Devi gave Kumar $80, he changed all the $80 to $5 notes. Then the number of notes Devi has now is 10% more than Kumar. How many notes does Devi have at the end????


Please help

[Jazpy]

Angel25:

Hi, Can someone help me with this Remainder Concept Qn.


Wiki had some beads. He gave 2/5 of them to his brother. 1/3 of the remaining beads were shared among his three friends. if each friend received 45 lesser than the amount received by Wiki's brother, how many beads did Wiki have at first??

5/5 - 2/5 = 3/5 (remainder)

1/3 of the remainder = 1/3* 3/5 = 1/5
So 1/5 of Wiki's beads are given to his 3 friends.

1/5 divided by 3 = 1/15 (Each of the 3 friends will get 1/15 of his beads)

2/5 - 1/15 =5/15

5/15 of Wiki's bead = 45
1/15 =9
15/15 =135

So wiki had 135 beads at first

[tigerslayer]

Angel25:

Beatrice arranged some beads in 15 short rows and 14 long rows. there were 36 more beads in each long row than each short row. Beatrice used 70% of the beads she had to arrange the beads in long rows while the rest of the beads were arranged in short rows. How many beads were there in each short row?

steps and explanations pls

15 Short rows = 15 * X number of beads (15x)
15x = 30% of total beads
divide both by 15 (highest common denominator)
x = 2% of total beads

29x + (36 * 14) = 100% of beads
29x = 58% of total beads
36*14 = 504 = 42% of total beads
504/42 = 12 = 1% of total beads

12 * 58 = 696 = 29x
696 / 29 = x = 24

24 beads per short row

[Jazpy]

Angel25:

Beatrice arranged some beads in 15 short rows and 14 long rows. there were 36 more beads in each long row than each short row. Beatrice used 70% of the beads to arrange in long rows while the rest of the beads were arranged in short rows. How many beads were there in each short row?


steps and explanations pls

70% of her beads are arranged into 14 long rows.

14L => 70%
1L => 5%
100% =>20L (if she uses all her beads for Long rows she can arrange 20 Long rows)


30% => 15S
2% => 1S
100% => 50S (if she uses all her beads for short rows she can arrange 50Short rows)

no of beads for 20L = no of beads for 50S

20x36=720 (20L will have 720 more beads than 20S)

50 - 20 = 30

30S = 720
1S = 24

ANS= 24

[atutor2001]

Angel25:

Beatrice arranged some beads in 15 short rows and 14 long rows. there were 36 more beads in each long row than each short row. Beatrice used 70% of the beads to arrange in long rows while the rest of the beads were arranged in short rows. How many beads were there in each short row?


steps and explanations pls

Let me try using the standard Pr sch method.

70% of the beads to arrange in long rows while the rest of the beads were arranged in short rows means that Ratio of Total number of beads in long row : Total number of beads in short row = 70 : 30

Ratio of number of beads in 1 long row : number of beads in 1 short row
= 70/14 : 30/15
= 5 : 2

No. of beads in 1 long row - No. of beads in 1 short row = 5U - 2U = 3U

3U is 36
1U is 12
2U is 24 (number of beads in 1 short row)