Dan has 20 books in his library. he bought several books at a yard sale over the weekend. he now has 71 books in his library. how many books did he buy at the yard sale?

Determine the volume of a cylinder bucket if the diameter is 8.5 in. and the height is 11.5 in.

Amountain climber starts a climb at an elevation of 453 feet above sea level at his first rest stop he has climbed 162 feet and by his second rest stop he has climbed another 207 feet its getting late in the day so the climber starts his way down if the climber desends 285 feet how much does he need to ascend or descend to return to the original starting point

Joline is solving the equation 0=x^2-5x-4 using the quadratic formula which value is the negative real number solution to her quadratic equation round to the nearest tenth if necessary