Question

the average of five numbers is 9. The average of 7 other numbers is 8. What is the average of all 12 numbers..... These are the options given:

Answer 1

\[8\frac{ 5 }{ 12 },8\frac{ 3 }{ 4 },8\frac{ 7 }{12 },8\frac{ 11 }{ 12 }\]

Answer 2

Since average is 9, sum of 1st 5 numbers=9*5=45
in same way,sum of next 7 numbers=8*7=56
so the sum of 12 numbers=45+56
so average=(45+56)/12
can u simplify this?