I think B. is the correct answer i hope i helped
Answer:
Step-by-step explanation: We are asked to find the distance covered by a man in 15 minutes at a speed of 16 km/hr. 15 minutes = 15/60 hour. Therefore, the person can run 4 km in 15 minutes.
Explanation:
A. The radioactive decay equation is N = N0
where T is the
half-life (5730 years), N0 is the number of atoms at time t = 0 and
N is the number at time t.
Rewriting this as:
(N/N0) = 
Since N = (1/8) N0 and
substituting known values:
1/8 = 
Taking ln of both
sides:
ln(1/8)= -ln(2)*t/5730
t = - 5730 * ln(1/8) /
ln (2)
t = 17,190 years
The tree was cut down 17,190
years ago.
B. N0 = 1,500,000 carbon-14 atoms
Since N = (1/8) N0
N = 187,500 carbon
atoms left
I think because each element has its own number of protons and neutrons, giving it its own atomic number and mass (correct me if I’m wrong please)