Need help with math problems

9. Suppose only the top 20 % of marks on a university entrance exam quaiies an application for admission. If the test results had a mean of 400 and standard deviation of 25 what is the minimum score for admission? [31'] ID. Suppose approximately 95 96 of people who wrote a standardised test had marks that ranged from 7'8 to 92 and the results were norrnalhir distributed. What is the standard deviation? [Assume the marks between 78 and 92 were centered about the mean}. [31']