First Calculate the sq. Ft of the Fence that is as follows 6 x 25 = 150 so he has to paint 150 sq. Ft so the amount of time taken is as follows he can pain a sq. Ft by 5 minutes ( i.e. 10 /2 ) so will take 750 minutes or 12 hours 30 minutes ( i.e. 5 x 150) Hope you got your answer