Question

An element with an initial mass of 618 grams decays by 2.1% per minute. How much of the element, to the nearest gram, will remain after 4 hours?

Answer 1

Element remaining =${mass \times(1-r/100)^t}$

4hrs= 240mins

$={618\times(1-2.1/100)^{240}}$

$=3.8g$