the average of 9 observations was 4 , that of the 1 st of 5 being 10 and that of the last 5 being 8 . what was the 5 th observation ?
"explanation : 1 to 9 = 9 * 4 = 36 1 to 5 = 5 * 10 = 50 5 to 9 = 5 * 8 = 40 5 th = 50 + 40 = 90 – 36 = 54 option a"
subtract(add(multiply(10, 5), multiply(4, 5)), multiply(4, 9))