Q&A - PSLE Math

[Winx5015]

Hi charsen,


:thankyou:

[charsen]

Winx5015:

Hi, please help!


http://i45.tinypic.com/fa7x4i.jpg\">

Hi
This is my attempted answer.If any mistakes in the working, inconvenience
cause regretted.
6u-->54
1U--9
Alice paid-->9-7.45=$1.55
Actual money to be paid by each---->54/3=18
Ali money--->9x5=45
extra money paid by Ali --->45-18=27.
amount of money paid by meimei to ali---->18-7.45=$10.55(ANS)
amount of money paid by Alice to Ali--->18-1.55=$16.45(ANS)
cheers

[verykiasumummy]

hi charsen,


r u a tutor or teacher?

[trytry]

susutoo:

hi,

sorry forget to attached image
http://i45.tinypic.com/nqusdd.jpg\">

Sum of area of quadrant and area of semi circle=22/7x7x7x3/4=115.5
Area of rectangle card=91.5+115.5=207
Find factor of 207=9x23
G&C: Length of rectangle 23cm (21+2),Breadth=9cm (7+2)
Perimeter=23x2+9x2=64cm

[MathIzzzFun]

susutoo:

hi,

sorry forget to attached image
http://i45.tinypic.com/nqusdd.jpg\">

alternate approach :

fill in the unshaded with the area of quadrants and semi circle
--> 3/4 x 22/7 x7 x7 = 115.5 cm2

Total area of the rectangle = 115.5 + 91.5 = 207 cm2

The breadth and length of the card are whole numbers
--> 207 = 23 x 9

perimeter of rectangular card = (23+9) x 2 = 64 cm

cheers.

[charsen]

verykiasumummy:

hi charsen,


r u a tutor or teacher?

Refer to your Private Im just a psle student. Pls bear with any wrong answers ad im also learning.

[tianzhu]

Winx5015:

Hi, please help !


http://i46.tinypic.com/r1m0k5.jpg\">

Hi

b) 8 grey, 56 white

c) figure 14

Best wishes

[peggy]

Thanks, Tianzhu!

[Winx5015]

Thanks charsen and tianzhu.


Good nite

[MathIzzzFun]

zombie:

Can someone teach me or help to solve these questions using the constant difference/unchanged total method ? Thanks a lot ! :oops:


1) \tThere were 165 more chickens than ducks on a farm. If 60% of the chickens and 20% of the ducks were sold, the number of chickens left will be twice the number of ducks left. How many chickens were sold?

Left --> 40% (=2/5) of chickens and 80% (=4/5) of ducks

Chickens left : Ducks left = 2 : 1 --> 8 units : 4 units

Number of chickens at first --> 8 units ÷ 2/5 = 20 units
Number of ducks at first --> 4 units ÷4/5 = 5 units

There were 165 more chickens than ducks, so
20 units - 5 units = 15 units --> 165
1 unit --> 11

Number of chickens sold --> 3/5 x 20 x 11 = 132

cheers,