A motorist covers 177.5 km in 2 hours. On the open road he averages 105 km/h
and 40 km/h in urban areas. How many minutes did he take to pass through the
urban areas?

-- James.

Let us assume that the motorist took x hours to cross urban areas. Therefore he travelled for 2-x hours on open road.

Therefore (x *40 + (2-x)*105) = 177.5
=> 40x+210-105x = 177.5
=> 65x = 32.5
=> x = 0.5 hours = 30 mins

The motorist took 30 mins to pass through urban areas.

-- James