Ali works as a tutor for $10 an hour and as a waiter for $12 an hour. This month, he worked a total of 99 hours at his two jobs. Let be the number of hours Ali worked as a tutor this month. Write an expression for the combined total dollar amount he earned this month.
Let's call the number of hours Ali worked as a tutor this month "t".
The number of hours Ali worked as a waiter this month is then 99 - t.
The amount of money Ali earned as a tutor this month is 10t, and the amount of money he earned as a waiter this month is 12(99 - t).
The combined total dollar amount he earned this month is 10t + 12(99 - t).
Let's call the number of hours Ali worked as a tutor "t". Since Ali worked a total of 99 hours at his two jobs, the number of hours he worked as a waiter would be 99 minus the number of hours worked as a tutor (99 - t).
To calculate the combined total dollar amount Ali earned this month, we need to multiply the number of hours worked at each job by their respective pay rates and then add the two amounts together.
The amount Ali earned as a tutor would be $10 multiplied by the number of hours worked as a tutor (10t), and the amount he earned as a waiter would be $12 multiplied by the number of hours worked as a waiter (12(99 - t)).
Adding these two amounts together gives us the expression for the combined total dollar amount Ali earned this month:
10t + 12(99 - t)
To write an expression for the combined total dollar amount Ali earned this month, let's first determine the number of hours he worked as a waiter. Let's call this number W.
We know that Ali worked a total of 99 hours at his two jobs. So, the number of hours he worked as a tutor can be calculated as follows:
Number of hours worked as a tutor = Total hours worked - Number of hours worked as a waiter = 99 - W
Now, let's calculate the amount Ali earned as a tutor and as a waiter:
Amount earned as a tutor = Number of hours worked as a tutor × Hourly rate as a tutor = (99 - W) × $10
Amount earned as a waiter = Number of hours worked as a waiter × Hourly rate as a waiter = W × $12
Finally, to find the combined total dollar amount Ali earned this month, we add the amount earned as a tutor and the amount earned as a waiter:
Combined total dollar amount earned = Amount earned as a tutor + Amount earned as a waiter = (99 - W) × $10 + W × $12
Therefore, the expression for the combined total dollar amount Ali earned this month is (99 - W) × $10 + W × $12.