vaishali jhalani please check for any typo ...QS updated !
yes grammar is ambiguous so priority couldnt be decided(in general case)
but here they have explicitly mentioned that we have to evaluate the expression ..so we have 2 choices either give priority urself or use their gramamar and decide(this is what we have to do..see their levels )....if they would have mentioned everything in one line like E→E+E / E∗E / E−E / (E) / id..then there was a confusion which was having higher priority...but again they have given grammar in levels..saying treat lowest with highest priority..
NOTE:for ambiguous grammars precednce is nt defined..we can play with it according our needs or according to their needs...this question is about satisfying their worries..!
see this one..little bit messy though..!
This is the sdt tree..
X->YZ , Y->XZ , ...