TheRCcompanyrentsbusesfromagencyXat26%ofthe time , agencyY at38% of the time , and agency Z at the remainder ofthetime. It is knownthat 10 % of thebuses from agencyX , 20 %ofthebusesfromagencyY, and5 % of thebusesfromagencyZhave defectivetires.Ifabusisrandomlyselectedfromacentralpoolofbuses fromtheseagencies, findtheprobability that

a)Thebushasdefectivetires

b)The busisfromagencyX, givenithasdefectivetires

c)ThebusisfromagencyZ, givenit hasnon defectivetires