25. Probability question bank (Mathematics)

The three ships namely $A$,$B$ and $C$ sail from India to Africa. If the odds in favour of the ships reaching safely are $2:5$,$3:7$ and $6:11$ respectively,then the probability of all of them arriving safely is

Three critics review a book. For the three critics,the odds in favour of the book are $(5: 2)$,$(4: 3)$ and $(3: 4)$ respectively. The probability that the majority is in favour of the book is