There is a bag with only red marbles and blue marbles. The probability of randomly choosing a red marble is 2 9 . There are 45 marbles in total in the bag and each is equally likely to be chosen. Work out how many red marbles there must be

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.