Question

The average of 9 numbers is 30. The average of first 5 numbers is 25 and that of the last 3 numbers is 35. What is the 6th number.​

Answer 1

Step-by-step explanation:

average = (sum of all numbers) /number of numbers

average of 9 number =30

that means sum = 9*30=270

so sum of 9 numbers =270

the average of first 5 numbers is 25

so sum of first five numbers = 25*5=125

and last there numbers = 3*35= 105

so add both 125+105= 230

but sum of 9 numbers =270

and sum of 8 numbers =230

missing 6th number =270-230= 40