Every package of a certain toy also includes 2 batteries.

1. Are the number of toys and number of batteries in a proportional relationship? If so, what are the two constants of proportionality? If not, explain your reasoning.
2. Use for the number of toys and for the number of batteries to write two equations relating the two variables.

Lin and her brother were born on the same date in different years. Lin was 5 years old when her brother was 2.

A student argues that does not represent a proportional relationship between and because we need to multiply one variable by a constant to get the other one, not divide by a constant. Do you agree or disagree with this student?

In one version of a trail mix, there are 3 cups of peanuts mixed with 2 cups of raisins. In another version of trail mix, there are 4.5 cups of peanuts mixed with 3 cups of raisins. Are the ratios equivalent for the two mixes? Explain your reasoning.