A(r)=3.12r2. what is the value of a(5)

What is the solution to the equation? k/6.4=8.7 2.3 5.568 15.1 55.68

Aubrey read 29 books and eli read 52 books what number is equal to the number of books aubrey read?

Plz answer asap! i will reward brainliest and 12 points for these three questions!take notice: these three questions are completely different! 1) what is the percentage of sugar in the syrup made of 10 kg of water and 4 kg of suugar? 2) what was the original price if after 10% discount it became $450? 3) at first a price was decreased by 12%, then it was disounted again by an additional 5%. what is the percent of the total discount? , and remeber i will award brainliest and 12 points!