Q&A - PSLE Math

[tianzhu]

Essential:

Hi need help in this question . Eliza usually jogs at an average speed of 100/min and takes 24 minutes to reach the park. If she jobs at 20m/ mim slower than her usual speed. How much longer will she take to reach the park?

Hi

I think this question is from paper 1.

Apply the formula, Distance ------- S*T

D -------- 24*100 ------ 2400

S -------- 80

T -------- 2400/80 ------- 30

30 - 24 ------ 6

She’ll take 6 minutes longer.

Best wishes

[jewelbox]

Hi, how do i solve the following qns? Thanks.

Mr Tan earned $3600 more that Mr Lim. After Mr Tan spent 20% o his salary and Mr lim spent 70% of his salary, Mr Tan had $3430 more than Mr lim in the end. If Mr lim was given a pay increment of 15%, find Mr Lim’s new salary.

[Winx5015]

Hi, need help for the following questions.


(1). The time taken for 10 workers to complete a construction job is 6 days more than the time taken for 12 workers to finish the same job. What is the number of workers required so that the time taken to finish the construction job is 21 days less than the time 10 workers took?

(2). If Allan and Bob work together, they can complete a job in 12 days. If they work together for 3 days, followed by Bob who worked alone for the next 5 days, they can finish 5/12 of the job. How many days will each of them need to complete the job if they were to work alone?

(3). Pool A and Pool B were filled to the brim with water. The taps at Pool and Pool B were turned on at 1pm and 2.30pm respectively to empty the pools. At 5pm, the water level in both pools were the same. At 6.30pm, Pool B was completely empty while Pool A was still filled with water. At 7pm, Pool A was completely empty. It was given that Pool A was 0.8 higher than Pool B in depth. If the rate of flow of water from each tap was kept constant, what was the height of Pool A.

Thanks!

[tianzhu]

jewelbox:

Hi, how do i solve the following qns? Thanks.

Mr Tan earned $3600 more that Mr Lim. After Mr Tan spent 20% o his salary and Mr lim spent 70% of his salary, Mr Tan had $3430 more than Mr lim in the end. If Mr lim was given a pay increment of 15%, find Mr Lim's new salary.

Hi

Before

Mr Tan -------- 10 units + 3600
Mr Lim -------- 10 units

After

Mr Tan -------- 8 units + 2880
Mr Lim -------- 3 units

8 units + 2880 ------- 3 units + 3430

5 units ------- 550
1 unit ------ 110

Mr Lim’s salary ------- 1100

After 15% increment ------- 1100*1.15 -------- 1265

Best wishes

[jewelbox]

Thanks Tianzhu, you make the soln look so simple and I always wonder why I didnt see it earlier. :slapshead:

[kklau]

Hi Tianzhu,


Many thanks for your reply and the mentioned P6 Maths question was taken from South View Pri. School revision paper, the diagram was re-drawn and the shaded areas could be differs. Perhaps your diagram could be the correct one!

Thank you again for pointing the error and looking forward for your good solution soon.

Best Regards.

[rose michelle]

The figure below shows 3 different rectangles, X, Y ad Z. 3/10 of X and 40% of Z is shaded. The shaded area of X is the same as the shaded area of Z. What fraction of the figure is unshaded if 60% of Y is shaded?

[small]

tianzhu:

kklau:

Hi,


Re-post and I would be very much appreciate that anyone could help to provide solution to this P6 maths question.

The diagram below 2 quadrants and a circle in a square of edge 10cm. Find the area of the shaded region (Take π = 3.14)

http://i47.tinypic.com/10fv18n.png\">

Thank you.

Best Regards.

Hi

Could you share where is your question from?

I've seen one similar question some years ago, but the shaded areas differs slightly.

Best wishes

http://farm8.staticflickr.com/7089/7152307519_7fa3e70673_z.jpg\">

Hi kklau,

I hope my working will not confuse you.

http://i47.tinypic.com/33x78nn.jpg\">

[speedmaths.012624com]

Winx5015:

Hi, need help for the following questions.


(1). The time taken for 10 workers to complete a construction job is 6 days more than the time taken for 12 workers to finish the same job. What is the number of workers required so that the time taken to finish the construction job is 21 days less than the time 10 workers took?

Hi,

Ratio of workers is 10:12.
Ratio of time taken will be 12:10, or 36:30.

10 workers will take 36 days; Job → 10 x 36 → 360 man-days.
12 workers will take 30 days; Job → 12 x 30 → 360 man-days.

10 workers will take 36 days.
Number of workers needed to complete job in (36 - 21 or) 15 days is:
360 man-days / 15 days → 24 workers.

Hope this helps.

Cheers


speedmaths.com


.

[MathIzzzFun]

Winx5015:

Hi, need help for the following questions.


(1). The time taken for 10 workers to complete a construction job is 6 days more than the time taken for 12 workers to finish the same job. What is the number of workers required so that the time taken to finish the construction job is 21 days less than the time 10 workers took?

(2). If Allan and Bob work together, they can complete a job in 12 days. If they work together for 3 days, followed by Bob who worked alone for the next 5 days, they can finish 5/12 of the job. How many days will each of them need to complete the job if they were to work alone?

(3). Pool A and Pool B were filled to the brim with water. The taps at Pool and Pool B were turned on at 1pm and 2.30pm respectively to empty the pools. At 5pm, the water level in both pools were the same. At 6.30pm, Pool B was completely empty while Pool A was still filled with water. At 7pm, Pool A was completely empty. It was given that Pool A was 0.8 higher than Pool B in depth. If the rate of flow of water from each tap was kept constant, what was the height of Pool A.

Thanks!

Hi

Q3.
Total time taken for Pool A to empty = 1900h - 1300h = 6h
Total time taken for Pool B to empty = 1830h - 1430h = 4h
At 5pm,
Pool A → 2/6 = 1/3 filled with water
Pool B → 1.5/4 = 3/8 filled with water
1/3 A = 3/8 B
3/9 A = 3/8 B
A--> 9 units, B --> 8 units
1 unit → 0.8m
Pool A → 9 x 0.8m = 7.2 m
Pool B → 8 x 0.8m = 6.4 m

cheers.