Answer:
0.018 pounds
Explanation:
First, convert each measurement to pounds from tons. We know there are 2,000 pounds in a ton, so for the supersaurus, 45/2,000 will give us the weight in pounds. This ends up equaling 0.0225. For the argentinosaurus, we divide 81/2,000 to get 0.0405. To find how much heavier the argentinosaurus is, we can subtract 0.0225 from 0.0405 to get 0.018 pounds as our final answer.