HCU MCA 2015 Paper

A student was studying in her room when the electricity failed. She had two new candles of different thickness but same length on her desk. She lit them and went on studying. The next day her father wanted to know ho long the electricity failure last. The student had not noted the times of failure and restoration of electricity. The student was worried since later last night she had cleared out her desk and thrown away the stubs, but she did remember that one stub was 4 times longer than the other, and informed the same to her father. Her father was now happy since he knew that the thicker candle lasts for 5 hours while thinner one takes 4 hours only. Using this information, the time of electricity failure was calculated as;