$\"\"$

\

The average of five numbers is $\"\"$ .

\

The average of $\"\"$ other numbers is $\"\"$ .

\

Find the average of all $\"\"$ numbers.

\

\

Let $\"\"$ be the sum of the five numbers.

\

$\"\"$ (Original propotion)

\

$\"\"$ (Cross product)

\

$\"\"$ (Multiply)

\

Let $\"\"$ be the sum of the $\"\"$ other numbers.

\

$\"\"$ (Original propotion)

\

$\"\"$ (Cross product)

\

$\"\"$ (Multiply)

\

$\"\"$ (Substitute $\"\"$ and $\"\"$ )

\

$\"\"$ (Add: $\"\"$ )

\

$\"\"$ (write as mixed fraction)

\

Therefore, the average of all $\"\"$ numbers is $\"\"$ .

\

$\"\"$

\

Option F is right choice.