arith metic progression

Asked by  | 12th Oct, 2008, 10:22: AM

Expert Answer:

Let the four parts be a-2d , a-d , a+d , a +  2d

So a-2d + a-d +   a+d +  a +  2d = 20

a = 5

[(a - 2d) (a +2d) ] / [( a-d) (a + d)]   = 2/3

a2 -  4 d2] / [a2  -  d2  ]  =  2/3

 3 aa  - 12 d2  =  2a2  --  2d2

a2  -  10 d2  =  0

 d = 5/  10

So  AP is  (substitute in  a-2d , a-d , a+d , a +  2d )

 

Answered by  | 12th Oct, 2008, 10:31: PM

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