Mitch and his friends are planning a trip to the Tsunami Springs water park. The employee Mitch spoke to on the phone said the total cost for all 7 of them would be $154. This includes an entrance ticket and a $5 tube rental fee for each person. What is the cost of an entrance ticket?

Let x be the cost of an entrance ticket.

The cost of 7 entrance tickets is 7x.
The tube rental fee for each person is $5, so the total tube rental fee for 7 people is 5 * 7 = $<<5*7=35>>35.
The total cost for all 7 people is the cost of the entrance tickets plus the total tube rental fee, so 7x + 35 = 154.
Subtracting 35 from both sides of the equation, we get 7x = 154 - 35 = 119.
Dividing both sides of the equation by 7, we get x = 119 / 7 = $<<119/7=17>>17.
The cost of an entrance ticket is $17. Answer: \boxed{17}.

To find the cost of an entrance ticket, we need to subtract the tube rental fee from the total cost.

The total cost for all 7 people is $154, and each person has a $5 tube rental fee.

So, the total tube rental fee for all 7 people is 7 * $5 = $35.

Now, subtracting the tube rental fee from the total cost, we have $154 - $35 = $119.

Since the total cost includes both the tube rental fee and the entrance ticket, the cost of the entrance ticket is $119.

To find the cost of an entrance ticket, we first need to determine the total cost of the tube rentals. According to the given information, there is a $5 tube rental fee for each person. Since there are 7 people in total, the total cost of the tube rentals would be 7 * $5 = $35.

Next, we subtract the tube rental fee from the total cost to find the cost of the entrance tickets. The total cost for all 7 people is $154 and the tube rental fee is $35, so the cost of the entrance tickets would be $154 - $35 = $119.

Therefore, the cost of an entrance ticket is $119.