1. Suppose the mass of a snowflake is about 10^-6 grams. What is the mass, in grams, of a snowball that contains similar 4.3 x 10^7 snowflakes? Show your work.

2. The school bookstore has 28boxes of crayons in stock. Some of the boxes contain 10crayons and some of them contain 25crayons. If there are a total of 535crayons in all, how many of each box does the store have in stock? Set up and solve a system of equations to solve the problem. Show your work.