Q2) Logic for Fibonacci Series

Q3) There are 100 doors in a row, all doors are initially closed. A person walks through all doors multiple times and toggle (if open then close, if close then open) them in following way: In first walk, the person toggles every door In second walk, the person toggles every second door, i.e., 2nd, 4th, 6th, 8th, … In third walk, the person toggles every third door, i.e. 3rd, 6th, 9th, … ……… ………. In 100th walk, the person toggles 100th door. Which doors are open in the end?

Q4) How to Measure 45 minutes using two identical wires?

Q5) All same as Q4 but this time i was given to calculate 15 min with the same wire? He also mentioned to give an out of box approach.