To determine when Miguel and Christina will have the same amount of gas in their tanks, we can set up equations based on their gas usage and capacities.
Let:
- \( M \) represent the amount of gas Miguel has after \( t \) weeks.
- \( C \) represent the amount of gas Christina has after \( t \) weeks.
Miguel's gas:
- Initial capacity: 20 gallons
- Usage: 1.5 gallons per week
- Amount left after \( t \) weeks: \[ M = 20 - 1.5t \]
Christina's gas:
- Initial capacity: 16 gallons
- Usage: 1 gallon per week
- Amount left after \( t \) weeks: \[ C = 16 - t \]
Set the amounts equal to each other: \[ 20 - 1.5t = 16 - t \]
Now solve for \( t \):
- Rearranging gives: \[ 20 - 16 = 1.5t - t \]
- Simplify: \[ 4 = 0.5t \]
- Divide both sides by 0.5: \[ t = 8 \]
So, after 8 weeks, Miguel and Christina will have the same amount of gas in their tanks.
The correct answer is: After 8 weeks they will have the same amount of gas in their tanks.