The skate shop owner wants 30% of each order to include long boards he wants to know how many long boards to order out of a total of 50 skateboards

What is the 17th term in the arithmetic sequence in which a6 is 101 and a9 is 83

9.4.34  question   to estimate the height of a stone  figure, an observer holds a small square up to her eyes and walks backward from the figure. she stops when the bottom of the figure aligns with the bottom edge of the  square, and when the top of the figure aligns with the top edge of the square. her eye level is 1.811.81 m from the ground. she is 3.703.70 m from the figure. what is the height of the figure to the nearest hundredth of a  meter?

Can anyone explain to me how to do this? anything will .