Plzzz help I’m struggling

Compute the standard deviation of the following set of data to the nearest whole number. 10, 10, 15, 20, 25

Suppose 38 lbs of coffee beans are required to produce 2 lbs of farmer's coffee. how many lbs of coffee beans are required to produce 309 lbs of farmer's coffee?

Write a function rule for  “the output is  5 less than the input.” let  xx  be the input and let  yy  be the output.