Sam’s brother is 7 years older than sam. his mother is 4 less than 3 times sam’s age. their combined age is 63. how old is sam, his brother, and his mother

The mean of a set of data is -3.82 and its standard deviation is 2.31. find the z score for a value of 3.99.

How many solutions does the nonlinear system of equations graphed bellow have?

Awater holding tank measures 105 m long, 50 m wide, and 8 m deep. traces of mercury have been found in the tank, with a concen- tration of 60 mg/l. what is the total mass of mercury in the tank? answer in units of kg.