for a certain exam , a score of 42 was 5 standard deviations below mean and a score of 67 was 2.5 standard deviations above mean . what was the mean score for the exam ?
"mean - 5 sd = 42 mean + 2.5 sd = 67 by solving above equations we get , sd ( absolute value ) = 3.33 mean = 58.67 ans . d"
divide(add(multiply(42, 2.5), multiply(67, 5)), add(5, 2.5))