A carbon sequestration facility is commissioned to remove carbon dioxide from the atmosphere. On the first day of operation, it captures 18.2518.2518.25 tonnes of CO2CO_2CO2. Each subsequent day, due to system calibration, the amount captured increases by exactly 1.251.251.25 tonnes over the previous day's total. The facility continues this process until a specific cumulative target is reached.
(i) State, with a reason, whether an arithmetic or a geometric series should be used to model the amount of CO2CO_2CO2 captured.
(ii) Write down an expression, in terms of nnn, for the mass, CnC_nCn, in tonnes, captured on day nnn.
Given that the facility's total sequestration target is 250025002500 tonnes, determine the number of days of operation required to reach this target.
