SOLUTION: if average of 9 subject is 60 , if average of first five subject is also 60 and average of last 5 subject is 55 then what is the fitft number??

Question 854671: if average of 9 subject is 60 , if average of first five subject is also 60 and average of last 5 subject is 55 then what is the fitft number??
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = the sum of the 1st 4 numbers
Let = the 5th number
Let = the sum of the last 4 numbers
-------------------------------------------------
(1)
(1)
----------------------------
(2)
(2)
------------------------
(3)
(3)
---------------------------
---------------------------
(2)
and
(3)
---------------------------
Substitute (2) and (3) into (1)
(1)
(1)
(1)
(1)
The 5th number is 35
---------------------
check:
(2)
(2)
(2)
and
(3)
(3)
(3)
and
(1)
(1)
(1)
(1)
OK -you can check (2) and (3)

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