Final answer:
Tiffany will need to buy a new bottle of detergent after 5 weeks, as she will use a total of 150 fluid ounces, with 25 fluid ounces remaining which is not enough for another full week's wash.
Step-by-step explanation:
The question asks how many weeks Tiffany can use a 175 fluid ounce bottle of detergent if she uses 30 fluid ounces each week.
To find the number of weeks that Tiffany can use the detergent,
we can divide the total fluid ounces in the bottle by the amount she uses each week.
Number of weeks = Total fluid ounces in bottle / Fluid ounces used per week
Number of weeks = 175 fluid ounces / 30 fluid ounces per week
Number of weeks = 5.8333 weeks
Since Tiffany cannot use a fraction of a week's worth of detergent, we round down to the nearest whole number.
Therefore, Tiffany will need to buy a new bottle of detergent after 5 weeks.