The average of 9 results is 45 . If the average of the first four results is 44 and that of the last four is 47 , the fifth no. is :

41

Average  of 9 results = 45

 Sum of these 9 results = 405

Sum of first four numbers = 44 × 4 = 176

Sum of last four numbers = 47 × 4 = 188

∴ 5th number = Sum of all numbers  - ( Sum of first four numbers + Sum of last four numbers )

5th number  = 405 - ( 176 + 188 ) = 41