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put this solution on YOUR website!Harold calculated the mean of 5 numbers to be 68.
Let n = sum of the 5 numbers

= 68
n = 5*68
n = 340
Then he found that he made an error and had written 70 for one of the numbers when he should have written 80.
This raises n by 10, 350 is the correct sum

= 70 is the correct mean