Answer
688,000 tons
Work Step by Step
Multiply to find the annual weight and convert to tons. Note the cancellation of units in the numerators and denominators.
$\frac{4.4\ lb}{1\ person}\times312,780,968\ person\times\frac{1\ ton}{2000\ lb}$
$=1,376,236,259.2\ lb\times\frac{1\ ton}{2000\ lb}=68\underset\uparrow8,118.126\ ton$
The number to the right of the thousands digit is less than 5 so round down.
