Question

Examine the following situations and determine which represents a function rule:

Maya pushes the Mountain Dew button on a soda machine and receives a can of Mountain Dew. She then pushes the same Mountain Dew button again and receives a can of Mr. Pibb this time.
Ariel earns $10 for each hour she babysits.
The size of a carton and the number of presents in the carton.
Phineas weighs 156 pounds. When Phineas's parents measured his height, his mom says he is 63 inches tall while his dad says Phineas is 70 inches tall.

Answer 1

Examine the following situations and determine which represents a function rule:

Maya pushes the Mountain Dew button on a soda machine and receives a can of Mountain Dew. She then pushes the same Mountain Dew button again and receives a can of Mr. Pibb this time.

Ariel earns $10 for each hour she babysits.

The size of a carton and the number of presents in the carton.

Phineas weighs 156 pounds. When Phineas's parents measured his height, his mom says he is 63 inches tall while his dad says Phineas is 70 inches tall.

Answer 2

for a function, every input must have a unique output (when you input some quantity x, it must always return y. if the same input generates multiple outputs, then it's not a function)

this is easier to see with one of the examples. for example, in the soda example, since the mountain dew button generated mountain dew the first time, but pibb the second time, this isn't a function.

repeat this kind of logic with the other options to find the right choice.