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.
The answer is 10 quarters because 10 quarters would be $2.50. You would need 3 more nickles to get $2.65. 10 would be 7 more than 3.
I'm pretty sure the answer is D. because I don't think anyone would want to take their total meal cost and then multiply it by their tip to make it even larger. You would just add the tip to the meal cost.