THIS USER ASKED ๐Ÿ‘‡

The half-life of a certain radioactive material is 78 hours. an initial amount of the material has a mass of 790 kg.. write an exponential function that models the decay of this material. find how much radioactive material remains after. 18 hours. round your answer to the nearest thousandth

THIS IS THE BEST ANSWER ๐Ÿ‘‡

half – life in = 78 hours
the amount after 39 hours is 395 kg:
395 = 790e ^ (k * 78)

Sharing about 790 and taking a natural log
ln (395/790) = (k * 78)
-0.6931 = 78k
-0.00888 = k

lets calculate the remaining 18 hours:
Size (18)
= 790e ^ (- 0.00888 * 18)
Size = 673.301 kg
I hope this helps