Q&A - PSLE Math

[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:

[2632parent]

Urgently need your help on the following 2 questions


1) If Mrs Tan transfers 1 girl from the Math club to the English club. 1/7 of the remaining members in the Math club will be girls. However if she transfer 2 boys instead to the English club then 1/5 of the remaining pupils in the Math club will be girls. What is the total number of boys and girls in the Math club.

2) Faizai had a total of 461 male and female goldfish. He gave away 60% of the male goldfish and 1/3 of the goldfish for the charity fund raising project. Then he bought 30 female goldfish. As a result, the number of female goldfish he had was 25% the number lof male goldfish left.
a) How many male goldfish did he have at first?

b) The next day, 16 male goldfish and 14 female goldfish died. What percentage of goldfish left was the female goldfish?


Many many thanks

[lakshmi v]

Can anyone help fast?


Mr Ang had 600 red and blue balloons altogether. After he sold 20% of his red balloons and bought another 60 blue balloons, the number of blue balloons was 2/5 the number of red balloons. How many red than blue balloons were there at first?

Thanks in advance.