Since since distance=speed times time we can write s=20t1=10t2 where s is the distance to school and t1 and t2 the travelling times to and from school. Also t1+t2=1 hour.
So 2t1=t2 and t1+t2=t1+2t1=1, so 3t1=60 mins, and t1=20 mins, t2=40 mins.
So it takes Jose 40 minutes to walk home.