
By: whitety (offline) Tuesday, May 31 2011 @ 09:45 PM CDT (Read 2418 times)



whitety 
Hi,
Need some help on 2 P5 maths qns :
1) The ratio of Jane's mass to Peter's mass was 7:10. When Jane's mass was increased by 12.3kg and Peter's mass was decreased by 7.5kg, they would have the same mass. Find Peter's original mass.
2) A bus left the interchange with some passengers. At the first busstop, 1/10 of the passengers alighted and 9 passengers boarded the bus. At the second busstop, 2/5 of the passengers alighted and 8 passengers boarded the bus. There were 35 passengers on board the bus before it stopped at the third busstop. How many passengers boarded the bus at the interchange ?
Thanks for the help!

Newbie
Registered: 05/22/11 Posts: 4





By: chiucc2006 (offline) Wednesday, June 01 2011 @ 04:21 AM CDT



chiucc2006 
I am not sure if the answer is correct.
J: P
7:10
Jane would be 12.3kg + 7.5kg lighter than Peter.
3 units would be 19.8kg
1 unit would be 19.8kg divide by 3
Peter's original weight would be 66kg.

Newbie
Registered: 12/31/06 Posts: 2





By: chiucc2006 (offline) Wednesday, June 01 2011 @ 04:39 AM CDT



chiucc2006 
Find multiples of 10
20,20,30,40,50
You have to do some guess and check
I did and found that 40 is the answer
1/10 of 40 is 4.
4 people alighted from the bus.
36 people are left.
9 people boarded the bus.
So 45 people are on the bus before the second busstop.
2/5 of 45 is 18.
18 people alighted form the bus.
27 people are left.
8 people boarded the bus.
So 35 people are on the bus before the third busstop.
40 people boarded the bus at the interchange.

Newbie
Registered: 12/31/06 Posts: 2





By: joannleesw (offline) Wednesday, June 01 2011 @ 08:09 PM CDT



joannleesw 
For Q2, there is no guess work required but it can be worked backwards.
3/5 units + 8 = 35
1/5 unit = 9
5/5 units = 45
9/10 units + 9 = 45
1/10 unit = 4
10/10 units = 40
Therefore, 40 passangers boarded the bus at the interchange.

Newbie
Registered: 05/31/11 Posts: 1





By: whitety (offline) Wednesday, June 01 2011 @ 11:21 PM CDT



whitety 
Thanks for the great help!

Newbie
Registered: 05/22/11 Posts: 4





learnandshare 
This question can be solved using the bar diagam.
Imagine there are 10 units : draw a bar with 10 segments. Once 1/10 of the passenger has alighted, you are left with 9 units.
Let the 9 units be called 9U and equate it to x; 9U= x
At the second stop, draw a bar with 5 segments but each of this segment is not equal to 1U. Let each of the segment be represented as V.
5V = x+9 (9 is added due to 9 passengers boarded the bus at station 1)
Hence, 2/5 of the passengers has alighted, you would have, have left with 3V before the 8 passengers board the bus at station 2.
Once the 8 passengers joined in, we would have 3V + 8 = 35.
Hence, V =9
x = 5(9) 9
x=36
Since from the start we know, 9U = x, hence; U= 4
Initially we have 10U which equates to: 10 *4 = 40 passengers.
Just try drawing it with blocks, and you will have a better appreciation of the question.

Newbie
Registered: 06/03/11 Posts: 2





By: whitety (offline) Sunday, June 05 2011 @ 10:25 PM CDT



whitety 
Thanks for the help! Will try and understand all the different methods.

Newbie
Registered: 05/22/11 Posts: 4



