Numbered discs are placed in a box and one disk is selected at random. if there are 7 red discs numbered 1 through 7, and 4 yellow disks numbered 8 through 11, find the probability of selecting a disk numbered 3, given that a red disk is selected

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.