The average of 11 results is 30. If the average of the first five is 25 and that of the last five 28, then find the sixth result.

65

Total of 11 numbers = 11 × 30

Total of 1st five numbers = 5 × 25

Total of last five numbers = 5 × 28

ATQ,

(11 × 30)  = (5 × 25) + 6th no. + (5 × 28)

5 (11 × 6) =  5 (28 + 25) + 6th no.

5(66) - 5 (53) = 6th no.

5(66 – 53) = 6th no.

6th no. = 5 × 13

6th no. =  65