Subtracting fractions with unlike denominators

Acertain standardized? test's math scores have a? bell-shaped distribution with a mean of 520 and a standard deviation of 105. complete parts? (a) through? (c)

Seymour is twice as old as cassandra. if 16 is added to cassandra’s age and 16 is subtracted from seymour’s age, their ages become equal. what are their present ages? show !

Adam used 1072.4 gallons of water over the course of 7 days. how much water did adam use, on average, each day?