Q&A - PSLE Math

[htn]

A quick one, so sorry no time to draw today.


I’ll provide some pointers.

Radius of quarter circle (AD) ----- 12

Diameter of small semi circle (AD or BC) ------ 12

Length AB of rectangle (AB) -------- 28

Perimeter of shaded area ------ (3.1412) + 16 + 16 ------ 69.68

Area of shaded part ------ (2812) – (3.14*12)/2 ------- 336 – 226.08 ------109.92

Best wishes[/quote]

Thanks, Vanilla Cake and tianzhu

how to get AD ----- 12?

[tianzhu]

Heeheehaha:

Please help in the following Question, TIA

1.Aimei, Bala & Carl won some money in a lucky draw. The amount of money won by Aimei, Bala & Carl wasi n the ratio 8: 5 : 4. They saved some of the money & spent the rest. Aimei saved $480, Bala saved $540 & Carl saved $120. The amount of money spent by AImei, Bal & Carl was in ratio 8:3:5
(a) Find the ratio of the amount of money saved by Aimei to Bala to Carl. Give your answer in its simplest form
(b) How much money did Aimei win ?

Hi

(a) A:B:C ----- 480:540:120 ----- 8:9:2

(b) Amount of money won
A:B:C ------- 8u:5u:4u

Amount of money saved
A:B:C ------- 480:540:120

Amount of money spent
A:B:C ------- 8p:3p:5p

8u - 8p -----480 -----Aimei
1u – 1p ------60
3u – 3p -----180

5u - 3p ---- 540 ----Bala
2u ---- 540-180
2u -----360
1u -----180

Aimei ----- 8u ------ 1440.

Best wishes

[tianzhu]

Heeheehaha:

2. 6A & 6B had an equal number of pupils. 6A had twice as many boys as 6B but 6B had 3 times as many girls as 6A.

(a) Find the ratio of the number boys in 6A to the number of girls in 6B( Give your answer in its simplest form)
(b) If there are 36 girls in 6B, how many more boys are there in 6A than 6B ?

Hi

You may use MD.

I unit of boy ----- 2 parts of girls.

(a)B:G ------4:3


(b) 3 parts -----36
1 part -----12

1 unit -----24

24 more boys in 6A than 6B

Best wishes

[Heeheehaha]

tianzhu:

Heeheehaha:

2. 6A & 6B had an equal number of pupils. 6A had twice as many boys as 6B but 6B had 3 times as many girls as 6A.

(a) Find the ratio of the number boys in 6A to the number of girls in 6B( Give your answer in its simplest form)
(b) If there are 36 girls in 6B, how many more boys are there in 6A than 6B ?

Hi

You may use MD.

I unit of boy ----- 2 parts of girls.

(a)B:G ------4:3


Dear Tianzhu,
Can u explain in more detail how to get answer (a) 4:3;
Thanks

(b) 3 parts -----36
1 part -----12

1 unit -----24

24 more boys in 6A than 6B

Best wishes

[MathIzzzFun]

Heeheehaha:

tianzhu:

[quote=\"Heeheehaha\"]2. 6A & 6B had an equal number of pupils. 6A had twice as many boys as 6B but 6B had 3 times as many girls as 6A.

(a) Find the ratio of the number boys in 6A to the number of girls in 6B( Give your answer in its simplest form)
(b) If there are 36 girls in 6B, how many more boys are there in 6A than 6B ?

Hi

You may use MD.

I unit of boy ----- 2 parts of girls.

(a)B:G ------4:3


Dear Tianzhu,
Can u explain in more detail how to get answer (a) 4:3;
Thanks

(b) 3 parts -----36
1 part -----12

1 unit -----24

24 more boys in 6A than 6B

Best wishes

[/quote]Hi

this similar problem sum may help..

http://www.flickr.com/photos/62167097@N02/5760364658/in/photostream

cheers.

[Despair]

Sorry for the trouble, five tough questions,


1. Mr Foo started to travel from Town P to Settlement Q on his limousine at 10 30 at an average speed of 48km/h. After taking a rest for 45 min, he continued travelling from Settlement Q to City R at an average speed that was 1.5 times his earlier average speed. He arrived at City R at 15 00. Given that the distance between Settlement Q and City R is 30 km less than the distance between Town P and Settlement Q, find the distance between Town P and City R.

[Despair]

Despair:

Sorry for the trouble, five tough questions,


1. Mr Foo started to travel from Town P to Settlement Q on his limousine at 10 30 at an average speed of 48km/h. After taking a rest for 45 min, he continued travelling from Settlement Q to City R at an average speed that was 1.5 times his earlier average speed. He arrived at City R at 15 00. Given that the distance between Settlement Q and City R is 30 km less than the distance between Town P and Settlement Q, find the distance between Town P and City R.

http://www.onsponge.com/forum/35-thinkingmathonsponge/13507-rosyth-2011-prelim-paper-mind-boggling-questions.html#13510

For the rest of the questions

[Andrew Lee]

Hi, how to solve this?

http://i54.tinypic.com/rcshzd.jpg\">

[MathIzzzFun]

Despair:

Sorry for the trouble, five tough questions,


1. Mr Foo started to travel from Town P to Settlement Q on his limousine at 10 30 at an average speed of 48km/h. After taking a rest for 45 min, he continued travelling from Settlement Q to City R at an average speed that was 1.5 times his earlier average speed. He arrived at City R at 15 00. Given that the distance between Settlement Q and City R is 30 km less than the distance between Town P and Settlement Q, find the distance between Town P and City R.

Hi

Total travelling time from P to R = 1500 - 1030 - 45min = 3h 45 min = 225 min

From Q to R, Mr Foo travelled at 48 km/h x 1.5 = 72 km/h

Add a point X after R such that XR = 30 km. Now PQ = QX and assume that Mr Foo travelled at 72km/h for the distance XR = 30km, so he will taken another 30/72 x 60 = 25 min. Total time taken from P to X = 225 min + 25 min = 250 min

Speed ratio - speed PQ : speed QX = 48 : 72 = 2 : 3
Time ratio - Time taken to travel PQ : Time to travel QX = 3u : 2u
5u = 250 min, 1u = 50 min

So, total distance from P to R
= 3u x 48 km/h + 2u x 72km/h - 30km (since we have added an arbitrary distance of 30 km)
= 3 x 50/60 x 48 + 2 x 50/60 x 72 - 30
= 210 km

cheers.

[MathIzzzFun]

Andrew Lee:

Hi, how to solve this?

http://i54.tinypic.com/rcshzd.jpg\">

Hi

please check question ...

http://i52.tinypic.com/30ug1e0.jpg\">

cheers.