When did Mahatma Gandhi establish the Sabarmati Ashram in Ahmedabad?

Which one of the following Ashrams related to Mahatma Gandhi, is the oldest?

At the time of India’s Independence, Mahatma Gandhi was:

When did Gandhiji give the slogan of ‘Swaraj in a year’?

The twin principles of Mahatma Gandhi’s Ram Rajya were?

What was the age of Mahatma Gandhi when he returned to India from South Africa?