## THIS USER ASKED ๐

**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 ๐

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