A job seeker is attending an interview in a company. The interview is in three parts, namely, aptitude, written and verbal. The probabilities of him passing the aptitude test, written test and verbal test are 0.7, 0.6 and 0.5 respectively. Find the probability of him (a) passing all the tests. (b) failing all the tests. (c) passing at least two of the tests. (d) passing one test.​