In a housing society, the probability that a randomly chosen family subscribes to a Hindi daily is 0.6, that it subscribes to an English daily is 0.4, and that it subscribes to both is 0.2. What is the probability that a randomly chosen family subscribes to at least one of the two dailies?

For any two events, $P$(A or B) = $P(A)+P(B)-P$(A and B) = 0.6 + 0.4 − 0.2 = 0.8. The subtraction matters because the families taking both papers were counted once in each of the first two figures. Trap 1.0 adds 0.6 and 0.4 without removing that double count, and it should look suspicious — it claims every single family takes a paper. Trap $0.24=0.6\times 0.4$ multiplies as though the two habits were independent, which the given 0.2 shows they are not. Trap 0.6 just repeats the Hindi figure.