Need math help really bad?

I need help with math, I'm in pre-algebra having a hard time with percentages, I have questions like this.........In a survey of 100 people, 27 preferred relish on their hot dogs. What % preferred relish?.......Question 2....The adult dosage for medicine is 100 mg for every 20lbs of body weight. If the person weighs 240lbs and he is to recieve a dose of his meds every 3hrs find the amount of meds he should recieve in each dose........