#### Explanation:

$I = P \times R \times T$

If you are unfamiliar with this equation,

$\text{Interest" = "Price" xx "Rate (as a decimal)" xx "Time (in years)}$

$I = 6000 \times 6.25 \times 0.25$

I = $9375 $\therefore$The student must pay back $9375 interest to the bank.