The average of five numbers is nine. The average of seven other numbers is 8. What is the average of all 12 numbers

Answer 1

You might realize the average is between 8 and 9, a little closer to 8

weight the two averages by 5 for 9 and 7 for 8

(5x9 + 7x8)/(5+7)

=(45+56)/12

=101/12

= 8 5/12 = average of all 12 numbers

= 8.41666....