Final answer:
After paying back $1.50 of her $2.25 debt to her grandfather, Mariah currently owes $0.75.
Step-by-step explanation:
Mariah had owed her grandfather $2.25 and paid him back $1.50. To find out how much Mariah currently owes her grandfather, we need to subtract the amount she paid back from the original debt.
Step-by-step calculation:
- Original amount owed: $2.25
- Amount paid back: $1.50
- Remaining debt: $2.25 - $1.50 = $0.75
Therefore, Mariah currently owes her grandfather $0.75, which corresponds to option A.