Pounds a re a unit for measuring mass, not weight. Each gallon will weigh approx 275 poundals.
first class is delivered in 3 to 5 days
630 miles: one half = 315 miles in t1 hours, 45 mi/hr; 315 miles in t2 hours, 35 mi/hr315 = t1 x 45315/45 = t17 = t1315 = t2 x 35315/35 = t29 = t2Thus, the whole trip took 9 + 7 = 16 hours.