Respuesta :

(1 1/2)/(1/3) = 4 1/2 km/h
(6 3/4)/(4 1/2) = 1 1/2 
Peter would take one a and half hours to walk at the same pace
Convert km to m and hours to minutes
1500m in 20 minutes
1500/20=6750/x
6750/1500=4.5
20*4.5=90
convert to hours
90 minutes = 1.5 hours