Answer:
The answer is in the photo
Step-by-step explanation:
21 because 9+10 is actually 21
<span>As the age of the U-235 sample is 2.631 billion years, and the half-life of U-235 is 713 million years, the sample has undergone 2.361 X 1,000,000,000 / 713 X 1,000,000 = 3.69 half lives. In each half-life the sample reduces to half its original weight according to the radioactive Half-Life Formula:
ln (Nt /N0) = -kt, where N0 = mass of the original weight of radioactive material, Nt = mass of radioactive material at time t, k = decay constant and t = time interval . We have to put Nt/N0 = 1/2 for time interval = half-life.</span>
AB means A X B so you have to do 14 / 9 which is 1.5 or there abouts.
1/16
multiples 15,30,45,60, and 75 making 5/80 then you simplify to 1/16
