An adult human contains around 100,000,000,000,000 cells, each cell has 46 chromosomes so that would yield 4,600,000,000,000,000 strands but there is DNA in mitochondria too!
If you use the average of 75 trillion cells for an adult human body and assumed DNA present in every cell, at an average of 6 ft in length, you would come up with the following:DNA in ft=450...