The probability that you answer any question correctly is 0.6, while the probability of getting it wrong is 0.4. (where 1 means certain while 0 means impossible). The probability that you get exactly 4 questions correct is \(0.6\cdot0.6\cdot0.6\cdot0.6\cdot0.4\), but that is not the final answer, because there are 5 permutations of 4 correct answers and 1 incorrect, so we need to multiply that by 5 to get: \(0.6\cdot0.6\cdot0.6\cdot0.6\cdot0.4\cdot5\).
Can you finish it from there?