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Author Topic: Add Maths June 8, 10 2010  (Read 14409 times)

Offline jellybeans

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Re: Add Maths June 8, 10 2010
« Reply #30 on: May 30, 2010, 02:21:02 pm »
Quote from: J.Darren on May 30, 2010, 12:06:35 pm


Am I correct ???

heyyyeyy. how did you get the 54? ;D Lol
OH and np. hahaha, :P
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Offline theharrovian

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Re: Add Maths June 8, 10 2010
« Reply #31 on: May 30, 2010, 02:24:43 pm »
Yes, the MS is correct and so is J.Darren. Nice work from him in my opinion.
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Offline jellybeans

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Re: Add Maths June 8, 10 2010
« Reply #32 on: May 30, 2010, 02:42:09 pm »
Quote from: J.Darren on May 30, 2010, 02:20:31 pm
I do apologise :-[

...how did you get 54? for the distance i mean. :(
:) :)
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Offline J.Darren

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Re: Add Maths June 8, 10 2010
« Reply #33 on: May 30, 2010, 02:42:59 pm »
Quote from: jellybeans on May 30, 2010, 02:21:02 pm
heyyyeyy. how did you get the 54? ;D Lol
OH and np. hahaha, :P
36 * 1.5 (0600 to 0730 - 90 minutes / 1.5 hours) = 54
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Offline cooldude

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Re: Add Maths June 8, 10 2010
« Reply #34 on: May 30, 2010, 02:50:20 pm »
i have a question, y is the angle between the boat and the liner 45, it is stated that the bearing is 315 for the boat and 45 for the liner, so that means the boat is at a bearing of 315 as shown in my diagram, and the angle between them is 135 and not 45, so cud nebody explain me y is it 45 and not 135
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Offline jellybeans

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Re: Add Maths June 8, 10 2010
« Reply #35 on: May 30, 2010, 02:52:43 pm »
Quote from: J.Darren on May 30, 2010, 02:42:59 pm
36 * 1.5 (0600 to 0730 - 90 minutes / 1.5 hours) = 54

THANK YOU. ;)
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Offline Ghost Of Highbury

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Re: Add Maths June 8, 10 2010
« Reply #36 on: May 30, 2010, 03:11:28 pm »
The ms says 135 or 45 depending on the diagram...first, in darren's diagram, the 90km line is less than the 54 km line, u have to at least roughly make it longer...

plus check the diagram i have attached, it shows how the angle is 135 too..

i have a gce-o lvel past papers book and i just saw this question is in that book as a sample question paper, there , the answer says - 28.9 as i have exactly explained..

plz correct me if im rong
« Last Edit: May 30, 2010, 03:28:37 pm by A@di »
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Offline jellybeans

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Re: Add Maths June 8, 10 2010
« Reply #37 on: May 30, 2010, 03:22:38 pm »
Quote from: A@di on May 30, 2010, 03:11:28 pm
The ms says 135 or 45 depending on the diagram. im pretty sure the ms is incorrect...first, in darren's diagram, the 90km line is less than the 54 km line, u have to at least roughly make it longer...

plus check the diagram i have attached, it shows how the angle is 145 too..

i have a gce-o lvel past papers book and i just saw this question is in that book as a sample question paper, there , the answer says - 28.9 as i have exactly explained..



 :o so it has two answers? ..whaaaa?
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Offline theharrovian

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Re: Add Maths June 8, 10 2010
« Reply #38 on: May 30, 2010, 03:35:17 pm »
Quote from: A@di on May 30, 2010, 03:11:28 pm
The ms says 135 or 45 depending on the diagram...first, in darren's diagram, the 90km line is less than the 54 km line, u have to at least roughly make it longer...

plus check the diagram i have attached, it shows how the angle is 135 too..

i have a gce-o lvel past papers book and i just saw this question is in that book as a sample question paper, there , the answer says - 28.9 as i have exactly explained..

plz correct me if im rong

OK, I will correct you because you are wrong. Read the question - it says the ship is at a bearing of 315 from the lifeboat at 0600 hours. Your diagram shows that the ship is at a bearing of 315 from the lifeboat at 0730 hours instead of at 0600 hours.
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Offline cooldude

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Re: Add Maths June 8, 10 2010
« Reply #39 on: May 30, 2010, 03:37:27 pm »
Quote from: theharrovian on May 30, 2010, 03:35:17 pm
OK, I will correct you because you are wrong. Read the question - it says the ship is at a bearing of 315 from the lifeboat at 0600 hours. Your diagram shows that the ship is at a bearing of 315 from the lifeboat at 0730 hours instead of at 0600 hours.

now do u mind correcting me, thanks
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Offline Ghost Of Highbury

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Re: Add Maths June 8, 10 2010
« Reply #40 on: May 30, 2010, 03:43:44 pm »
ohkay got it, i realized that it is on the bearing at 0600 hours, because the q was clear, screwed up while making the diagram..thanks ..

and By the way, if u zoom the angle 315 has been marked correctly, the 45 shudnt have been there :P
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Offline theharrovian

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Re: Add Maths June 8, 10 2010
« Reply #41 on: May 30, 2010, 03:45:38 pm »
Quote from: cooldude on May 30, 2010, 03:37:27 pm
now do u mind correcting me, thanks

Your line AB is in the wrong direction - the question states "from the lifeboat", not "to the lifeboat". Otherwise your diagram is completely correct - you've just misread/misinterpreted the question and taken the lifeboat to be on a bearing of 315 from the liner.
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Offline Ghost Of Highbury

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Re: Add Maths June 8, 10 2010
« Reply #42 on: May 30, 2010, 03:47:22 pm »
Quote from: cooldude on May 30, 2010, 11:36:18 am
see the question is  basically asking what is the time taken for the boat to travel the dist AC, dist BC=54 because the speed of the liner is 36 km/h and the time it travels is 1.5 hrs thus the dist=1.5*36=54, the dist AC can be found out by the cosine rule, x=angle ABC
A^2=B^2+C^2-2ABcosx
A^2=90^2+54^2-(2*54*90*cos 135)
A=AC=133.75 km
therefore the speed of the boat = 133.75/1.5=89.2 km/h



The 315 degree bearing has been interpreted incorrectly, it shud be clockwise...bering B from A should be 315, in you case it isnt..
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Offline cooldude

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Re: Add Maths June 8, 10 2010
« Reply #43 on: May 30, 2010, 04:01:58 pm »
i finally understood my mistake, i took the bearing from the north direction when i was supposed to take it from the position of the liner at 600, Thanks guys  ;D
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Offline jellybeans

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Re: Add Maths June 8, 10 2010
« Reply #44 on: May 30, 2010, 04:20:32 pm »
... D:
help please ;D
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