A normal variable has a mean μ and a standard deviation σ. What is the probability that the value of the variable is greater than μ − σ? 80.1%, 74.1%, 90.2%, 84.1%

Serena is making an experiment. for that, she needs 20 grams of a 52% solution of salt. she has two large bottles of salt water: one with 40% and the other with 70% of salt in them. how much of each must she use to make the solution she needs? i am in need of