A bone fragment has 10% of the parent Pb-210 remaining. The half-life of Pb-210 is 22 years. How old is the bone fragment?

Ithink i know it but i want to be sure so can you me out ?

The graph shows the amount of total rainfall at each hour what was the total rainfall amount after three hours

A. the following events are mutually exclusive: living in california and watching american idol. true or false b. the number of patients seen by an outpatient practice is an example of a discrete random variable. true or false c.the law of large numbers states that as the number of times an event experiment is conducted increases, the likelihood of the actual probability of an event approaching the theoretical probability decreases. true or false d. measuring the time it takes for patients to enter the operating room is an example of a continuous random variable. true or false