what does the Borda count method do to preference schedules that is not the same as the condorcet method

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

What is the mean of the data set 125, 141, 213, 155, 281

Which shows one way to determine the facts of x3+4x2+5x+20 by grouping