To get a B in a course, you must have an average of at least 80% on four tests worth 100 points each. Your scores so far are 82, 91, and 73. What must you score on the fourth test to get a B in the course?

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