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?  Choose one.
A) 74	B) 76	C) 78	D) 58.67	E) 82.2

Rationale: "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"
Answer: D