How much a 2.00 g 239 Pu would have decayed after 1.6 x 10^4 years? The half-life for 239 Pu is 2.4 x 10^4 years.
amount remaining= originalamount*(.5)^(1.6/2.4)
amount decayed = original - amountremaining
amount remaining= originalamount*(.5)^(1.6/2.4)
amount decayed = original - amountremaining