Question

Tritium is a radioactive isotope of hydrogen that decays by about 5% per year. A large bottle of water that contained 520,000 tritium atoms remained undisturbed for 8 years. How much tritium does the bottle contain now?

Answer 1

Answer:

345,000 to the nearest thousand.

Step-by-step explanation:

5% = 0.05 as a decimal fraction.

After each year goes by,  1 - 0.05 = 0.95 of the tritium is left.

After 8 years Amount of tritium

=  520,000* (0.95)^8

=  344,979.