$$ \begin{array}{1} \text {There are } 350 \text { students in a class. Each of them takes a test with three questions } \mathcal{Q}_{1}, \mathcal{Q}_{2), \mathcal{Q}_{3} \text { Each student answers at least 1 \text { question. There are ) 260 \text { students who answered \mathcal{Q}_{1}, 100 \text { who answered } \mathcal{Q}_{2} \text { and } 70 \text { who answered } \mathcal(Q)_{3}, 40 \text { students answered } \mathcal{Q}_{1} \text { and } \mathcal{Q}_{2}, 40 \text { students answered } \mathcal{Q}_{2} \text { and } \mathcal{Q}_{3} \text { and ) 30 \text { students answered } \mathcal(Q)_{1} \text { and } \mathcal{Q}_{3} . \text { Find ) A \text { the i \text { number of students who answered all questions and ] B \text { the number of students who answered either question ) \mathcal{Q}_{2} \text { or } \mathcal{Q}_{3} \text { or both. W A=\square \quad \square \quad \square \quad \text { For sets } A, B, A cup B eg A \text { implies that ] B subseteg A \text {. W B \text { For arbitrary sets ] A, B, C \text { we have } A \cap(B. \cup C)=(A cup B) \cap (A \cup C) \text {.) \text { Decide which of sets] A, B, C \text { we have ) A \cup(B. \cap C)=(A \cap B) \cup (A cap C) \text { } \square \text { For subsets } B, C \text { of} A \text { we have ! A \backslash(B \backslash C)=(A \backslash B) \backslash C \text {. } \end{array} $$ SP.PB.099