What are some real world examples where percentages are used? How could you use percentages in your daily life?

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

Awindow washer cleans 42 windows in 2 hours. at this rate, how many windows did he clean in 180 minutes.

What are the domain and range of f(x)= -log5(x+2)