
By: geniuskids (offline) Tuesday, October 16 2012 @ 03:57 AM CDT (Read 908 times)



geniuskids 
Hi, pls help solve the questions:
Q5 : Please refer to the diagram on the test paper.
A and B are midpoints of the sides of the rectangle
What fraction of the rectangle is shaded?
(1) 1/4
(2) 3/8
(3) 5/8
(4) 3/4
Q11 : The avearge mass of a group of boys was 48kg.
When John joined the group, the new average mass of the group became 54kg.
If John weighed 72kg, how many boys were there in the group in the end?
(1) 9
(2) 8
(3) 6
(4) 4

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





By: geniuskids (offline) Saturday, October 20 2012 @ 09:33 PM CDT



geniuskids 
Hi there,
Q5 : managed to solved. quite simple. tks
Q11 : my solution : 5448 = 6
72÷6=12
48÷12=4
The answer is (4) 4, which we managed to get but don't really understand. Someone pls hep explain. Tks

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





By: EMY (offline) Sunday, October 21 2012 @ 03:37 AM CDT



EMY 
Hi Q11  don't know how to explain your working. Anyway, mine is:
if A = original number of people
and B = new number of people = A+1 (after John joins); then:
48A + 72 (John's mass) = 54B
so replacing B=A+1, it becomes:
48A + 72 = 54A + 54
6A = 18
A = 3
finally B = 3 + 1 = 4

Newbie
Registered: 10/21/10 Posts: 5





By: geniuskids (offline) Sunday, October 21 2012 @ 03:47 AM CDT



geniuskids 
hi, thanks for helping but yr method seems "complicated" for a P5.
I'll try to understand.
Thanks again

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



