Q. 154.2( 6 Votes )
The mean of six numbers is 23. If one of the numbers is excluded, the mean of the remaining numbers is 20. Find the excluded number.
Let suppose the numbers are = n1, n2, n3, n4, n5, n6
Given mean = 23
n1 + n2 + n3 + n4 + n5 + n6 = 23×6 = 136 ……….(i)
Let suppose excluded number be n4
N = 5
Mean of remaining numbers = (given)
n1 + n2 + n3 + n5 + n6 = 20 × 5 = 100 ……….(ii)
Subtract the (ii) equation from (i) equation
n4 = 138 – 100 = 38
So, the excluded number is 38.
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