Answer: 18.125 lbs
Explanation: The baby weighed 18.125 pounds at the end of eight months.
The baby weighed 7.25 lbs at birth. Eight months later, he weighed 2.5 or 2½ times its birth weight. Multiply 7.25 by 2.5 (which equals 18.125).
So now eight months later, he's 18.125 pounds.
Average speed = (distance covered in some time) / (time to cover the distance)
4 hours 45 minutes = 4-3/4 hours = 4.75 hours
Average speed = (3,800 km) / (4.75 hours) = 800 km/hr
