Bill is doing weight training before trying out for the boxing team. He gets two 2-gallon jugs and fills them 70% full with sand. If sand has a density of 5 pounds/gallon, how many pounds do Bill's improvised weights weigh?
First find the volume of the sand in one jug: 2 gallons * 70% = 
<gadget id="calculator">2*70*.01</gadget>
<output>1.4</output>
1.4 gallons.
Then double this amount since there are two jugs: 1.4 gallons * 2 = 
<gadget id="calculator">1.4*2</gadget>
<output>2.8</output>
2.8 gallons.
Then multiply the total volume by the density of sand to find the total weight: 2.8 gallons * 5 pounds/gallon = 
<gadget id="calculator">2.8*5</gadget>
<output>14</output>
14 pounds.

<result>14</result>