Question

Radon-222 decays at a continuous rate of 17.3% per day. How much will 170 mg of Radon-222 decay to in 7 days?



NOTE: Round your answer to 4 decimal places.

Answer 1

Radon-222 decays at a continous rate of 17.3% per day

At present,

The amount of Radon-222 is 17.3%

After first day,

The amount left after decay is = 170 - 17.3% of 170

After second day,

The amount left after decay is = 140.59 - 17.3% of 140.59

After third day,

The amount left after decay is = 116.26793 - 17.3% of 116.26793

After fourth day,

The amount left after decay is = 96.15357811 - 17.3% of 96.15357811

After fifth day,

The amount left after decay is = 79.519009097 - 17.3% of 79.519009097

After sixth day,

The amount left after decay is = 65.7622205232 - 17.3% of 65.7622205232

After 7 days,

The amount left after decay is = 54.3853563727 - 17.3% of 54.3853563727

This is the amout of Radon-222 left after 7 days,

The total amount decayed after 7 days is

As rounding off to 4 decimal places,

125.0233

Therefore,

125.0233mg of Radon-222 is decayed to 44.9767mg of Radon-222 after 7 days