Simple adding problem, help please!

[pman]

Hello,

My fan has 4 power level settings that cycles: 1,2,3,4, 1,2,3,4 and so on...

Assuming I cannot see or hear the fan, I cannot turn it off and it is always on some some current power level (C).
How can I find how many presses (P) it will take to reset level back to 1?

 

[stapel]

My fan has 4 power level settings that cycles: 1,2,3,4, 1,2,3,4 and so on...

Assuming I cannot see or hear the fan, I cannot turn it off and it is always on some some current power level (C).
How can I find how many presses (P) it will take to reset level back to 1?

Since you have no idea what is the current setting, there is no way to know how many presses will land you in the correct state.

In effect, you're asking what number to add to x, modulo 4, in order to get 1. But you're not allowed to know the value of x. You're being asked to solve "x + y = 1, mod 4" for the value of y, without knowing the value of x. This is not algebraically (or logically) possible. Sorry.

Perhaps the exercise is just poorly stated. What is the exact text of the homework exercise? Can your instructor shed any light or give any hints? Thank you!