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IGCSE MATHS Doubts

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haris94:
can u pls explain how u got your first step:
10/15 + 10/x = 1

Vin:

--- Quote from: A@di on May 06, 2010, 09:11:51 am ---10/15 + 10/x = 1

10x + 150
---------    =   1
     15x

10x + 150 = 15x

5x = 150

x = 150/5 = 30

30 days.

Im not sure abt this though

--- End quote ---


yup its right...i hav another method..

john n peter 10days =>   1 house
                  1 day  =>    1/10 house

john in 1 day  =>  1/15

so,  one day of john + peter =  one day of  john n peter together

1/15  +  x  =  1/10
(L.C.M)
 
1 + 15x
---------    =   1/10
   15

1  + 15x = 15/ 10

15x  =  15/10  -1
(LCM on right)

15x = 1/2

x = 1/30

peter paints 1/30 of house 1 one day...so he takes 30 days to paint one house :) :)

always try to convert any work to 1 day n solve..i find this method easy tho..dunno abt others..  :)
                   

Vin:

--- Quote from: haris94 on May 06, 2010, 09:29:30 am ---can u pls explain how u got your first step:
10/15 + 10/x = 1

--- End quote ---

days for..(time taken for)

john+peter/john  +  john+peter/peter  =  1 house

haris94:

--- Quote from: ~VIN1094~ on May 06, 2010, 09:44:25 am ---days for..(time taken for)

john+peter/john  +  john+peter/peter  =  1 house


--- End quote ---

hmm...yea got it Thanks
nice method By the way
 

Baladya:
This isn't only in triangles. Its also in Sine and Cosine rule. Sometimes they ask u to write the two answers for sinx under for example 180.. search google for the sine and cosine 'curve' for maths and u will understand what m saying.

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