A box contains 15 resistors. Ten of them are labeled 50 Ω and the other five are labeled 100 Ω.

(a) What is the probability that the first resistor is 100Ω?
(b) What is the probability that the second resistor is 100 Ω, given that the first resistor is 50 Ω?
(c) What is the probability that the second resistor is 100 Ω, given that the first resistor is 100 Ω?