Let A and B be two events, P{(_A U 3)\"): 0.6 and HAL-n B) = 0.1 . Let E be the event that either A or B but not both will occur. Then HERA u 3)): 1 1 ' 2 - 3 3 . 3 ~ 'b- a c - - d - e ' ( ) 4 ( ) 3 ( ) 3 ( ) 5 ( ) 4 L The class average of a test is 56 with a standard deviation of 5. The instructor adjusts the test marks in two steps. Step '1 is to add 2 marks to every test mark, and step 2 is to multiple the test marks in step 71 by 3. The standard deviation of the test marks after step 2 is (21)?) (b)7 ' (e) 15 (d) 18 (6) none ofthese