First, you need to figure out how much the boots weigh together. You can do this by subtracting 144.9 from 150.7.
150.7-144.9=5.8
Assuming each boot weights the same, you can divide 5.8 by 2 to find the weight of each boot.
5.8/2=2.9
Each boot weighs 2.9 pounds.
I hope this helps :)