You question is missing one important thing: 40 fluid Ounces of what?
3 pounds
40 ounces = 2.5 pounds
3 pounds.
That is 2.5 pounds
3
Eight hundred and forty pounds
Pounds can't be converted to fluid ounces. Pounds measure mass, while fluid ounces measure volume.
3 pints
44 fluid ounces is approximately 1,293.32 CUBIC centimetres, (not square.)
34 ounces = 2.125 pounds
There are 16 ounces in one pound so 40 X 16 is your answer.
Pounds can't be converted to fluid ounces. Pounds measure mass, while fluid ounces measure volume.