Final answer:
The man at the phone store made an error in his calculation. The correct new cost after the discount is $54.20.
Step-by-step explanation:
The man at the phone store made an error in his calculation. He claimed that the new cost after a $4.75 discount on a $58.95 plan is $11.45. However, this is incorrect. To find the new cost after the discount, we subtract the discount from the original cost. So, the new cost would be $58.95 - $4.75 = $54.20.