Question
A set contains ten numbers. The average of the first
six numbers is (x − 4), and the average of the last three numbers is (x + 2). The average of the entire set is 'x'. If the 7th number of the set is 40, then find the value of 'x'.Solution
Sum of the numbers of set = 10x Sum of first 6 numbers = 6(x − 4) = 6x − 24 Sum of last 3 numbers = 3(x + 2) = 3x + 6 ATP, 6x − 24 + 40 + 3x + 6 = 10x 9x + 22 = 10x x = 22
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