
By: geniuskids (offline) Saturday, September 21 2013 @ 08:56 AM CDT (Read 1691 times)



geniuskids 
Hi there,
I need to clarify these 2 questions. Pls show yr working too!
Answer key:
Q10) 1
Q15) 2
Thank you!

Active Member
Registered: 11/12/11 Posts: 169





By: echeewh (offline) Saturday, September 21 2013 @ 04:57 PM CDT



echeewh 
Hey <geniuskids>
For Q10, I got a feeling that you overlooked the question which states that the radius of the big semicircle is 14 cm (and not diameter).
Following is my worked solution:
Q10.
Circum of BSC (Big SemiCircle)
= (1/2) × 2 × pi × 14
=14 pi
Circum of 2 SSC (Small SemiCircle)
= 2 × (1/2) × 2 × pi × 7
=14 pi
Perimeter of figure
= 14 pi + 14 pi
= 28 pi
= 28 × (22/7)
= 88 cm
Ans: (1)
=========
Trust this helps.
Do let me know again if there's further clarification.
Cheers,
Edward

Active Member
Registered: 04/21/11 Posts: 625





By: geniuskids (offline) Saturday, September 21 2013 @ 08:42 PM CDT



geniuskids 
Thank you! Yes I overlooked Q10...due to tiredness that night!
For Q15, what stated is 3 teachers and 39 Primary Six students. But there was a cancellation from 39 to 36!
My answer is 10.5, so closer to Answer 2 but =I'm not sure if I'm correct as it shows a decimal for people. So I'm confused.

Active Member
Registered: 11/12/11 Posts: 169





By: echeewh (offline) Sunday, September 22 2013 @ 05:42 AM CDT



echeewh 
Hey <geniuskids>,
Your answer of 10.5 indicates there's enough space on the bus for a maximum of 10 students only , and not more. Hence the answer is Option (2). I got this same answer using 2 methods and the original question should stay as in there's no change to the original number of Primary Six students. It should still read as 39 as per the question and not 36.
Thank you .
Best regards,
Edward

Active Member
Registered: 04/21/11 Posts: 625





By: geniuskids (offline) Sunday, September 22 2013 @ 07:18 AM CDT



geniuskids 

Active Member
Registered: 11/12/11 Posts: 169



