Yes, Bobby will have enough money if he saves for 9 weeks. You can find this through either substituting w for 9 in the equation, or solving the equation itself.
Substituting:

Substitute w for 9.

Simplify.

Solve.
255 is greater than 250, so yes, he will have enough money saved.
Solving the equation:

Original Equation

Subtract 30 from both sides.

Divide both sides by 25.
The number of weeks he needs is 8.8. When rounding it up, you get 9.
Divide $16,500 by 26 to get gross amount per paycheck. Multiply that by .095 to get amount withheld.
Answer:
Each book cost $12.50 dollars.
Step-by-step explanation:
1,187.50 / 95 = 12.50
Answer: There were 10 students in the class on the first day.
Step-by-step explanation:
Let x be the number of students of the first day.
Given: A college writing seminar increased its size by 50 percent from the first to the second day.
i.e. Number of students on second day = (Number of students on first day)+(50% of Number of students on first day)
= x +50% of x
= x+0.50x
= (1.50)x
=1.50x
Since, it is given that the total number of students in the seminar on the second day was 15.
i.e. 

Hence, there were 10 students in the class on the first day.