arithmetic mean

Asked by pvandana | 28th Sep, 2008, 08:27: AM

Expert Answer:

let the terms be a1,a2,a3,.......,a9,a10

so we hav given  (a1+a2+a3+...........+a10) /10  = 6

or a1+a2+a3+...........+a10 = 60............(1)

also (a1+a2+a3+a4) / 4 = 7.5

or a1+a2+a3+a4 = 30............................(2)

now let the A.M. of last remaining terms be K

so  (a5+a6+...........+a10) / 6 =K

or a5+a6+...........+a10 = 6K...................(3)

subsitute values from (2)&(3) into (1)

30 + 6K = 60  ==>  K = 5

the mean of remaining terms is 5.

Answered by  | 28th Sep, 2008, 09:49: AM

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