Are the following sentences natural to a native ear?
1. Wow, I could have sworn that it was real. ( was talking about a fake snake)
2. I am struggling to solve the following problem with simulation.
3. How much does it cost, on average, to convert a free parking lot to paid parking?
[AmE - not a teacher]
All of them sound great, except "with simulation" in 2. You might try:
I am struggling to solve the following problem by using a/the simulation. (The simulation will help fix the problem.)
I am struggling to solve the following problem with the simulation. (The simulation is broken.)