A retraining grant of £3,150 is drawn down at £225 a week. After how many weeks is the grant used up?

1. Write the amount left as 3150 minus 225 times the number of weeks. 2. The grant is used up when the amount left is zero pounds. 3. So write 0 = 3150 - 225w and add 225w to both sides to get 225w = 3150. 4. Divide both sides by 225 pounds per week, which gives w = 14 weeks. 5. Check it: 225 pounds times 14 weeks is 3,150 pounds, exactly the grant. 6. Option B comes from dividing by 262.50 instead, a rounding of the weekly figure. 7. Option C comes from dividing 3,150 by 196.875, a third rounding of the weekly figure. 8. Option A comes from dividing 3,150 by 175, another rounded weekly figure. _Source: OpenStax College Algebra (CC BY 4.0), Ch 4 "Linear Functions", section 4.2 Modeling with Linear Functions_