Final answer:
a) Theresa would earn $30 after working 5 hours. b) The rule for this situation is y = 6x.
Step-by-step explanation:
a) To find out how much Theresa would earn after working 5 hours, we need to determine the constant of proportionality. From the given information, we know that when she works 2 hours, she earns $12. This means she earns $6 per hour (12/2). So, if she works 5 hours, she would earn 5 * 6 = $<<5*6=30>>30.
b) The rule for this situation can be represented by the equation y = 6x, where y represents Theresa's earnings and x represents the number of hours she works.