Find the final amount when 10500 is invested at 9% simple interest for 4 years

The given diagram shows the parts of a right triangle with an altitude to the hypotenuse. using the two given  measures, find the other four.

Can someone me find the original price? the discount is 5% and the sale price is $68.40

You coordinate volunteers for litter cleanup in local parks. your spreadsheet lists drivers and the number of seat belts in each driver’s car. the spreadsheet calculates the number of drivers (d) and the total number of seat belts (s). you want to know the maximum number of volunteers, besides drivers, that can be transported to the park in a single trip given that each person must have a seat belt of their own.