the probability of a snake being venomous is 0.5 the probability of a snake being not venomous or not an instant killer is 0.8 if it is known that a snake is venomous find the probability that it is an instant killer

What is the answer?

My approach would be as, 50% chance for being non venomous, then there is remaining 30%, for happening non instant killer, so 20% would be for an instant killer. So instant : slow = 20:30, or 2:3, as it given that snake is already venomous then the instant killer probability will be 2/5

yeah 2/5 but 0.5 is being venomous n u took 50% for non venomous didn't get this.