Could you please help with part b? 2.63 The structure shown in the figure below could be subjectto settlement problems. The likelihood of having a settlementproblem (event A) depends on the subsoil condition, in particu-lar, whether a weak zone exists in the subsoil or not. If there isa small weak zone (event S), the probability of A is 0.2; if theweak zone is large (event L), the probability of A becomes 0.6;last, if no weak zone exists (event N), then the probability of Ais only 0.05. Based on their experiences with the geology of theneighborhood and the soil information from the preliminary siteexploration program, the engineers in this case believe that thereis a 70% chance of no weak zone in the stratum underlying thestructure; however, if there is a weak zone, it would be twice aslikely to be small than large.StructureWeak zone?Large or small?(a) What is the probability that the structure will have a settle-ment problem? (Ans. 0.135)(b) Suppose an additional boring can be performed at the site togather more information about the presence of the weak material.The engineers judge that: If a large weak zone exists, it is 80%likely that the boring will encounter it; this encounter probabil-ity drops to 30% for a small weak zone. Obviously, the boringwill not encounter any weak material if the weak zone does notexist at all. Suppose the additional boring failed to encounter anyweak material:i. What is the probability of the presence of a large weakzone? (Ans. 0.023)ii. What is the probability of a small weak zone? (Ans. 0.163)iii. In this case, what is the probability that the structure willhave a settlement problem? (Ans. 0.087)

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Answer:----.                       Date:----01/10/2021