SOLUTION: four numbers have an average of 70. three of them have average 50. the forth number is

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Question 773986: four numbers have an average of 70. three of them have average 50. the forth number is
Answer by ramkikk66(644) About Me  (Show Source):
You can put this solution on YOUR website!
Average of 'n' numbers = total of the n numbers / n
So, sum of 'n' numbers = Average of the 'n' numbers * n
Average of the 4 numbers is 70. So their sum is 70*4 = 280
Average of the 3 numbers is 50. So the sum of 3 numbers = 50*3 = 150
So the 4th number = Sum of 4 numbers - sum of the 3 numbers = 280 - 150 = 130.
:)