Answer:

Explanation:
Given:
- average walking speed,

- average biking speed,

<u>According to given condition:</u>

where:
time taken to reach the building by walking
time taken to reach the building by biking
We know that,

so,



From reliable sources in the internet, the half-live of carbon-14 is given to be 5,730 years. In a span of 10,000 to 12,000 years, there are almost or little more than 2 half-lives. Thus, there should be
A(t) = A(0)(1/2)^t
where t is the number of half-lives, in this case 2. Thus, only about 1/4 of the original amount will be left.
B the mass of the solar object determines whether the gravity of the object unless the solar object has Sonic property's such as a neutron star which can be the size of Pluto but have the mass of 900 solar masses