Question

A radioactive substance decays at a continuous rate of 14.4 % per day. After 15 days, what amount of the substance will be left if you started with 140 mg? (a) First write the rate of decay in decimal form. r = (b) Now calculate the remaining amount of the substance. Round your answer to two decimal places.

Answer 1

Answer:(a) The rate of decay is 14.4% per day, which can be written as a decimal by dividing by 100: r = 0.144.

(b) The formula for continuous decay is given by:

A = A₀ * e^(-rt)

where A is the remaining amount of the substance after time t, A₀ is the initial amount, r is the rate of decay, and e is the mathematical constant approximately equal to 2.71828.

Plugging in the given values, we get:

A = 140 * e^(-0.144*15)

A = 140 * e^(-2.16)

A ≈ 47.23

Therefore, after 15 days, approximately 47.23 mg of the radioactive substance will be left, rounded to two decimal places.

Explanation: