Prawidłowa odpowiedź to C, ponieważ 

$\frac{410\text{km}}{6\text{h}15\text{min}}=\frac{410\text{km}}{6\frac{1}{4}\text{h}}=\frac{410\text{km}}{\frac{25}{4}\text{h}}=410\cdot \frac{4}{25}\frac{\text{km}}{\text{h}}=\frac{1640}{25}\frac{\text{km}}{\text{h}}=\frac{6560}{100}\frac{\text{km}}{\text{h}}=65,6\frac{\text{km}}{\text{h}}$