Simon bought a sandwich for 7.85 he pays it with a twenty dollar bill how much will he get back

20-7.85=12/15 he will get 12.15 in return

Step-by-step explanation:

chemists are often responsible for designing a chemical reaction and analyzing the products obtained from it. one significant part of designing a chemical reaction is determining the amount of each reactant that is needed and the amount of each product that will be produced. in order to do so, chemists use stoichiometry, the quantitative relationships between reactants and products.