Let Q represent the mass, in grams, of a quantity of Uranium 238 (238U), whose half-life is 18 years. The quantity of Uranium present after t years from an initial sample of 60 grams is given by the equation Q=60(12)t18/ . In how many years will the quantity Q remaining be 10 grams?

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.