Gourmet Eatery has a policy of automatically adding an 18% tip to every restaurant bill,
28866

5195.88

that's the answer because that is what you get when you find 18% of 28866

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).