Zachary went into a grocery store and bought 5 bananas and 2 mangos, costing a total of $5.50. Olivia went into the same grocery store and bought 6 bananas and 10 mangos, costing a total of $12.30. Write a system of equations that could be used to determine the price of each banana and the price of each mango. Define the variables that you use to write the system.