the average of 6 observations is 16 . a new observation is included and the new average is decreased by 1 . the seventh observation is ?
"let seventh observation = x . then , according to the question we have = > ( 96 + x ) / 7 = 15 = > x = 9 hence , the seventh observation is 9 . answer : c"
subtract(multiply(subtract(16, 1), add(6, 1)), multiply(16, 6))