Q&A - PSLE Math

[Robertpattinsonidle]

how to do this qsn? my answer is 16 but answer key says 15. is it right? http://i50.tinypic.com/21cz5eh.jpg\">

[Zhu99]

Robertpattinsonidle:

how to do this qsn? my answer is 16 but answer key says 15. is it right? http://i50.tinypic.com/21cz5eh.jpg\">

Monday to Friday ---> 3 x 5 = 15

Saturday to Sunday ---> 6 x 2 = 12

15 + 12 = 27

60/27 = 2 weeks remainder $6 ---> Start saving on Sat or Sun to get the least number of days --- 1 day

7 + 7 + 1 = 15

The least number of days is 15.

[jarenchuatw]

Thanks Tianzhu, you got the answer right again, and the methods used is clearly illustrated

[kay22]

Mark and Nani were heading for their school from their homes. Mark started walking at a speed of 30 m/mim. At 6.45 am, Mark passed Nani’s flat and Nani started walking to the school at a certain speed. At 7 a.m., Nani was 150m ahead of Mark.


a) Find the speed at which Nani was walking.
b) If Nani reached the school 8 min ahead of Mark, at what time did Mark reach the school?

[tianzhu]

kay22:

Mark and Nani were heading for their school from their homes. Mark started walking at a speed of 30 m/mim. At 6.45 am, Mark passed Nani's flat and Nani started walking to the school at a certain speed. At 7 a.m., Nani was 150m ahead of Mark.


a) Find the speed at which Nani was walking.
b) If Nani reached the school 8 min ahead of Mark, at what time did Mark reach the school?

Hi

It helps to have a simple diagram.

In 15 min, Mark covered 450m.

150 + 450 ------ 600

Nani’s speed ------ 40m/min

Mark walked 240 m in 8 min.

In 1 min, Nani walked 10m faster than Mark.

In 24 min, Nani walked 240m faster than Mark.

Nani reached [email protected]

Hence, Mark reached the school@ 7.17 am

Best wishes

[Robertpattinsonidle]

zeemimi:

jewelbox:

Hi, how do I solve this qn? Thanks. http://i47.tinypic.com/2j1si1k.jpg\">

(a) ¼ x 2 π 3 + ¼ x 2 π 2 + 3/4x2 π 1 = 4 π

(b)

(A) Area of big quad = ¼ π3x3 = 9/4 π
(B) Area of white space under medium quad = 2x2 – ¼ π2x2 = 4 – π
(C) Area of white space in rect under smallest quad = 2x1 – ¼ π1x1= 2 – ¼ π
(D) Area of semi circle = ½ π 1x1= ½ π
Area of shaded region = (A) – (B) – (C) + (D) = 6.57 cm2

can u explain the last step? i cant understand. thank you

[tianzhu]

Robertpattinsonidle:

can u explain the last step? i cant understand. thank you

Hi

If you prefer to deal with familiar shapes, here’s an alternate way.

At this moment, just days before PSLE, students should be well versed in dealing with familiar shapes.

I’ll leave you to do the calculations.

All the best to your PSLE.

Best wishes

http://farm9.staticflickr.com/8308/7981184268_7541c7b434_z.jpg\">

[Chenonceau]

http://i46.tinypic.com/2jez6fo.jpg\">


Can someone help? Thanks!

[maychang]

Hi, my dd had gotten the answer is 216 members in March, but the answer key is 432 membe

Can anyone help to confirm if the answer key is wrong? My dd said her answer is correct.
Thanks.

The numbers of members in swimming club increased by 25% in February compared to January.
However, the number of members in March dropped by 10% compared to February. If the difference in the number of members between January and February was 48, how many members were there in March?

[maychang]

Hi, my dd had gotten the answer is 216 members in March, but the answer key is 432 membe

Can anyone help to confirm if the answer key is wrong? My dd said her answer is correct.
Thanks.

The numbers of members in swimming club increased by 25% in February compared to January.
However, the number of members in March dropped by 10% compared to February. If the difference in the number of members between January and February was 48, how many members were there in March?