The sum of the reciprocals of four different natural numbers is 1.85. Which of the following could be the sum of the four numbers?
Natural numbers from 1 to n are written on board.One of the numbers was erased and the new average becomes 600/17. Find the erased number ?
If there were n numbers before, then now there will n-1 numbers left.
Now, if average is 600/17, that means n-1 is multiple of 17.
With Hit & Trial, I come out with n-1=68 as the sum will be 69X70/2=2415.
And as per average, sum of n-1 numbers will be: (600/17)X68=2400.
Therefore, missing number is 2415-2400=15.