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.
Instead of X put 5 and instead of y put 2
5+6(2)
5+12= 17
Distance = speed rate x time
Speed rate = 120 miles per hour
Time = 3 hours
Replacing:
D = 120 mph x 3 h = 360 miles
I am doing the same thing
30 tens = 30 x 10 = 300
300 ones = 300 x 1 = 300
300 is your answer
30 tens = 30 x 10 = 300
3 hundreds = 3 x 100 = 300
3 is your answer
<em>~Rise Above the Ordinary</em>