Rockets are launched until the first successful launching has taken place.if this does not occur within 5 attempts,the experiment is halted and...

Rockets are launched until the first successful launching has taken place.if this does not occur within 5 attempts,the experiment is halted and the equipment inspected.suppose that there is a constant probability of 0.8 of having a successful launching and that successive atempts are independent.Assume that the cost of the first launching is K dollars while subsequent launching cost K/3 dollars.whenever a successful launching take place,a certian amount of information is obtained which may be expressed as financial gain of,say 'C' dollars.if 'T' is the net cost of this experiment,find the probability distribution of T?