In this task you will be given an answer to a question. You need to generate a question. The answer given should be a correct answer for the generated question.
Q: The Indian independence movement was a series of activities whose ultimate aim was to end the British Raj and encompassed activities and ideas aiming to end the East India Company rule (1757 -- 1857) and the British Raj (1857 -- 1947) in the Indian subcontinent. The movement spanned a total of 91 years (1857 -- 1947) considering movement against British Indian Empire. The Indian Independence movement includes both protest (peaceful and non-violent) and militant (violent) mechanisms to root out British Administration from India.
A: 
how many decades did india's struggle for independence take