The most important part of the problem lies in the fact that the hours have to be converted to minutes before starting to solve the problem.
1 hour = 60 minutes
6 and half hours = (6 * 60) + 30 minutes
= 360 + 30
= 390 minutes
So the payment for 390 minutes is = 78 dollars
Then
The payment for 60 minutes = (78/390) * 60
= 2 * 6 dollars
= 12 dollars
So the rate of pay given is $12 per hour. I hope the procedure is easy enough for you to understand. You can always use this method for solving similar type of problems.
To find the amount of money you have left, first you must calculate how much you have. You can do this by multiplying the rate and the amount of hours that you worked.
$11.50 * 6.5 = $74.75
Now we have to calculate out how much it costs. We can do this by adding the price of the meal to 20% of the price of the meal.
$12 + $12(.20) = $14.40
Now to find how much you have left, simply subtract the cost from how much you made.
