A car travels 195 km in 3 hours. How long will it take to travel 520 km (in hrs.)?

Given that, a car travels 195 km in 3 hours.

By using the unitary method,

Time taken by car to travel 195 km. = 3 hours.

→ Time taken by car to travel 1 km. = $\frac{3}{195} \mathrm{hours}.$

Now, 

The time taken by car to travel 520 km. = $\left(\frac{3}{195} \times 520\right) \mathrm{hours}.$

$=\mathbf{ }\mathbf{8}\mathbf{ }\mathbf{hours}\mathbf{.}$

Therefore, the time taken by car to travel 520 km. = 8 hours