Q&A - PSLE Math

[tianzhu]

2DMommy:

Please help me with these two questions :

1) Jay bought some chocolates and gave half of it to Kay. Kay bought some sweets and gave half of it to Jay. Jay ate 12 sweets and Kay ate 18 chocolates and then the ratio of Jay's sweets to chocolates became 1:7 and the ratio of Kay's sweets to chocolates became 1:4. How many sweets did Jay have at first ?

Hi

Here's the solution to a similar question.

Hope this helps.

Best wishes

http://farm6.staticflickr.com/5045/5642609859_22462520cc_z.jpg\">

[Robertpattinsonidle]

this question seriously mind boggling.



Both shops ABC and XYZ , offered a 15% discount for the same type of mattress. If Mr Muthu were to buy from shop XYZ ,he would have paid $38.25 less than the discounted price in shop ABC. a) What was the discounted price in the shop ABC ?
b) the original price of the mattress in Shop ABC was $1510. what was the minimum percentage discount it must offer so that the discounted price in shop ABC would be lower than the discounted price in Shop XYZ? Give your answer correct to the nearest percent.

[paranoid]

The figure below is made up of Squares EFGH and PQRS, a circle and two identical semicircles. J and K are the midpoints of PQ and RQ respectively.

P, Q, R, and S are the midpoints of EF, FG, GH and EH respectively.

Use the calculator value of pi to find the total area of the shaded parts, correct to 2 decimal places.

http://i48.tinypic.com/339k95z.png\">

Thanks in advance.

[Ready2WORK]

paranoid:

The figure below is made up of Squares EFGH and PQRS, a circle and two identical semicircles. J and K are the midpoints of PQ and RQ respectively.

P, Q, R, and S are the midpoints of EF, FG, GH and EH respectively.

Use the calculator value of pi to find the total area of the shaded parts, correct to 2 decimal places.

http://i48.tinypic.com/339k95z.png\">

Thanks in advance.

Please note that you did not indicate the dimensions of the figure.
However, the steps to find out the answer are as follows.
http://i45.tinypic.com/awykh1.png\">
Therefore, the working is:
(Big square-small square/8)+(Circle-small square/4)

[MathIzzzFun]

paranoid:

The figure below is made up of Squares EFGH and PQRS, a circle and two identical semicircles. J and K are the midpoints of PQ and RQ respectively.

P, Q, R, and S are the midpoints of EF, FG, GH and EH respectively.

Use the calculator value of pi to find the total area of the shaded parts, correct to 2 decimal places.

http://i48.tinypic.com/339k95z.png\">

Thanks in advance.

this was disussed @pg 807... http://tinyurl.com/mathizzzfun-PeiChun-2012Prelim

cheers.

[tianzhu]

paranoid:

The figure below is made up of Squares EFGH and PQRS, a circle and two identical semicircles. J and K are the midpoints of PQ and RQ respectively.

P, Q, R, and S are the midpoints of EF, FG, GH and EH respectively.

Use the calculator value of pi to find the total area of the shaded parts, correct to 2 decimal places.

http://i48.tinypic.com/339k95z.png

Hi

Another way of looking at it.

Hope this helps.

Best wishes

http://farm9.staticflickr.com/8456/8029267245_7e1d87ca5f_z.jpg\">

[tianzhu]

Robertpattinsonidle:

this question seriously mind boggling.



Both shops ABC and XYZ , offered a 15% discount for the same type of mattress. If Mr Muthu were to buy from shop XYZ ,he would have paid $38.25 less than the discounted price in shop ABC. a) What was the discounted price in the shop ABC ?
b) the original price of the mattress in Shop ABC was $1510. what was the minimum percentage discount it must offer so that the discounted price in shop ABC would be lower than the discounted price in Shop XYZ? Give your answer correct to the nearest percent.

Hi
This question has been discussed on page 837.

For (a)

15% ------- 38.25

100% ------- 255 (discounted price in ABC)

For (b)

In this case, we are working based on the given original price of $1510

Discounted price in ABC -------- 1510*0.85 ------ 1283.50

Discounted price in XYZ -------- 1283.50 – 38.25 ------- 1245.25

1510 – 1425.25 ------- 264.75

264.75/1510*100% ------- 18%

Best wishes

[Ready2WORK]

Robertpattinsonidle:

this question seriously mind boggling.



Both shops ABC and XYZ , offered a 15% discount for the same type of mattress. If Mr Muthu were to buy from shop XYZ ,he would have paid $38.25 less than the discounted price in shop ABC. a) What was the discounted price in the shop ABC ?
b) the original price of the mattress in Shop ABC was $1510. what was the minimum percentage discount it must offer so that the discounted price in shop ABC would be lower than the discounted price in Shop XYZ? Give your answer correct to the nearest percent.

a) Difference: $38.25 (with discount)
With discount: $38.25 is 85 % of the difference, so $38.25/85*100=$45

b)Shop XYZ: $1510-$45=$1465
Discounted price in shop XYZ: $1465/100*85=$1245.25
Difference: $1510-$1245.20=$264.80
Minimum percentage: $264.80/$1510*100%=18%

Note: Answer is certified correct.

[vlim]

Ready2WORK:

Robertpattinsonidle:

this question seriously mind boggling.



Both shops ABC and XYZ , offered a 15% discount for the same type of mattress. If Mr Muthu were to buy from shop XYZ ,he would have paid $38.25 less than the discounted price in shop ABC. a) What was the discounted price in the shop ABC ?
b) the original price of the mattress in Shop ABC was $1510. what was the minimum percentage discount it must offer so that the discounted price in shop ABC would be lower than the discounted price in Shop XYZ? Give your answer correct to the nearest percent.

a) Difference: $38.25 (with discount)
With discount: $38.25 is 85 % of the difference, so $38.25/85*100=$45

b)Shop XYZ: $1510-$45=$1465
Discounted price in shop XYZ: $1465/100*85=$1245.25
Difference: $1510-$1245.20=$264.80
Minimum percentage: $264.80/$1510*100%=18%

Note: Answer is certified correct.

Well done r2w!... Seems like u are all ready for tomorrow ..! :rahrah:

[Ready2WORK]

Robertpattinsonidle:

this question seriously mind boggling.



Both shops ABC and XYZ , offered a 15% discount for the same type of mattress. If Mr Muthu were to buy from shop XYZ ,he would have paid $38.25 less than the discounted price in shop ABC. a) What was the discounted price in the shop ABC ?
b) the original price of the mattress in Shop ABC was $1510. what was the minimum percentage discount it must offer so that the discounted price in shop ABC would be lower than the discounted price in Shop XYZ? Give your answer correct to the nearest percent.

@Robertpattisonidle
Can you please check your question, if part a is correct? As it is, your part a can have multiple answers, and part b indicates the original price of the mattress in shop ABC, which can be used to find the discounted price too. :scratchhead: