Robin purchased 3 1⁄2 ounces of whole wheat cereal for $1.40. what is the cost per ounce?

1.40 / 3.5 is how you get the answer. 3.5 is 7/2 and 1.40 / (7/2) is 1.40 x 2/7 which is 0.4

40 cents an ounce, since you firstly convert the ounces into a decimal value of9 3.5. Then since you have to find out the unit rate, or cost per ounce, you will then divide the price ($1.40) by the ounces (3.5). This will then get you to 1.4/3.5, which then when calculated gives the answer of .4, equivalent to 40 cents.

The correct answer is -20y

It's like discovering the answer to a puzzle. the purpose in solving an equation is to find the value or values of the variable that makes it a true statement. any value of the variable that makes the equation true is called a solution to the equation.