To solve this problem, we need to determine the value of x, which represents the number of seconds it takes Jimmy to climb the first flight of stairs.
We know that each following flight takes 5 seconds more than the preceding one. Therefore, the time it takes to climb the second flight is x + 5 seconds, the time it takes to climb the third flight is x + 10 seconds, and so on.
The total time it takes to climb the first five flights of stairs is 150 seconds.
We can set up the equation as follows:
Time to climb the first flight + Time to climb the second flight + Time to climb the third flight + Time to climb the fourth flight + Time to climb the fifth flight = Total time to climb the first five flights
x + (x + 5) + (x + 10) + (x + 15) + (x + 20) = 150
Let's simplify and solve for x:
5x + 50 = 150
To isolate x, we subtract 50 from both sides of the equation:
5x + 50 - 50 = 150 - 50
5x = 100
To solve for x, we divide both sides of the equation by 5:
x = 100 / 5
x = 20
The value of x is 20.
The answer is: 20
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Climbing the first flight of stairs takes Jimmy X seconds, and each following flight takes 5 seconds more than the preceding one. It takes a total of 150 seconds to climb the first five flights of stairs. What is the value of unknown variable X?

### Answer:
