Question
Tue March 13, 2012 By:
 

Q:divide 20 into four parts which are in A.P. and such that the product first and fourth is to the product of second and third are in the ratio 2:3?

Expert Reply
Wed March 14, 2012
Let the numbers be a-3d , a-d , a+d , a+3d with common difference 2d
Sum = 20
So 4a = 20 , a = 5
Also (a-3d)(a+3d)/(a-d)(a+d) = 2/3
(a2 - 9d2 )/(a2 - d2) = 2/3
On solving we get
a = +-(5d) , d = 1 , -1
On sustituting the values of a and d we get series as
2 , 4 , 6 , 8 
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