Let x be the amount per hour at part - time job in dollars.

The amount of earning in 3 hours on Friday is 3x dollars.

The amount of earning in 6 hours on Saturday is 6x dollars.

The allowance of amount per week is 20 dollars.

The total amount per week is 92 dollars.

Therefore, the above situation represent the equation is .

Solve the equation for x.

Group like terms.

Combine like terms.

.

Subtract 20 from each side.

.

Divide each side by 9.

Cancel common terms.

.

The amount per hour at part - time job is 8 dollars.