Q&A - PSLE Math

[shawnlim88]

jonaandr:

Help needed for these 2 questions - many thanks in advance!


1) 2 , 5 , 17 , 71 , X , 2159
Study the above number pattern. Find the value of X.

Ans: 359, pls tell me why.

2) When Karen left her house and drove at an average speed of 56km/h, she would reach Town X at 1900. If she decided to drive at an average speed of 72km/h, she would reach Town X at 1700. At what time did she leave her house?

hi
Qn1: No idea.
Qn2:
S = Dist/TIme
Let Starting TIme Be S. Distance be D

56 = (D) / (19-S)
72 = (D) / (17-S)

cross multiply
72(17-S) = 56(19-S)
1224 -72S = 1064 - 56S
16S = 160
S = 10

starting Time at 10:00 hrs

not sure if this is correct

[MathIzzzFun]

jonaandr:

Help needed for these 2 questions - many thanks in advance!


1) 2 , 5 , 17 , 71 , X , 2159
Study the above number pattern. Find the value of X.

Ans: 359, pls tell me why.

Hi

where is this question from?

2nd number = 1st number x 2 + 1
3rd number = 2nd number x 3 + 2
4th number = 3rd number x 4 + 3
5th number = 4th number x 5 + 4 = 71 x 5 + 4 = 359

cheers.

[tianzhu]

2632parent:

Any one more question


1) Mr lim had some red and green beads. 60% of his beads were red and the rest were green. He lost some of his red beads and the percentage of the beads which were red decreased by 40%. He then had 760 red and green beads left. How meant red beads did he lose?

Many thanks in advance.

Hi

Good Morning.

Red ----- 60 units ------ 600

Green ----- 40 units

After a decrease of 40%

Red ----- 36 units ------ 360

36 + 40 ------ 76

76 units ------- 760

1 unit ------10

In the end, red ------ 360

Therefore, he lost 600 - 360 ---- 240

Best wishes

[Shimmer]

Need help !


The table below shows the admission fees to a circus for an adult and a child. There were 50 more children than adults at the circus. If a total of $5614 was collected, how many children were at the circus ? Given each adult admission fee is $25 Ang child admission fee is $8.

[tianzhu]

Shimmer:

Need help !


The table below shows the admission fees to a circus for an adult and a child. There were 50 more children than adults at the circus. If a total of $5614 was collected, how many children were at the circus ? Given each adult admission fee is $25 Ang child admission fee is $8.

Hi

You may use “Grouping Concept”.

Fees collected from 50 children ------- 400

5614 – 400 ------ 5214

Fees for 1 group or 1 set of (1 adult + 1 children) -------- 25 + 8 ------ 33

Number of groups ------- 5214/33 ------ 158

Number of children ------- 158 + 50 ----- 208

Best wishes

[pixiedust]

Would appreciate some help with this question.



http://i1197.photobucket.com/albums/aa424/pixie_dust8/mq6.jpg\">

[tianzhu]

pixiedust:

Would appreciate some help with this question.



http://i1197.photobucket.com/albums/aa424/pixie_dust8/mq6.jpg\">

Hi

This question has been discussed before.

Time taken by tortoise ----- 5.2/3 ------ 104min

For rabbit

60min -----20km
1min ----- 1/3km

1min -----1/3
2mins -----2/3
3mins -----3/3
4mins ----4/3
5mins -----5/3

Total distance travelled in 15mins ---- 5km

The rabbit takes 0.6min to travel remaining 0.2km

Total time taken -----100+15.6 ----115.6

Therefore 115.6 -104 ----11.6min

Best wishes

[YumYum]

Hi, would appreciate help for this Qn, part (b): thanks! http://i49.tinypic.com/2s8fok6.jpg\">

[tianzhu]

YumYum:

Hi, would appreciate help for this Qn, part (b): thanks! http://i49.tinypic.com/2s8fok6.jpg\">

Hi

This question has been discussed before.

Hope this helps.

Best wishes

http://farm7.staticflickr.com/6063/6139917034_a6c214361a_z.jpg\">

[YumYum]

tianzhu:

YumYum:

Hi, would appreciate help for this Qn, part (b): thanks! http://i49.tinypic.com/2s8fok6.jpg\">

Hi

This question has been discussed before.

Hope this helps.

Best wishes

http://farm7.staticflickr.com/6063/6139917034_a6c214361a_z.jpg\">

Tianzhu: thanks for your usual help