Read the passage below and solve the questions based on it.
Anu, Bunty, Christy and Dorthy are 4 salesmen. In the 1st year they received a commission of Rs 4,200 from their company and divided it in the ratio of 2:3:4:5. In the 2nd year the commission doubled, the amount was divided in the ratio of 3:4:5:2. In the 3rd year the commission was tripled when compared to the first year and they shared in the ratio of 4:5:3:2 and in the 4th year the commission was half compared to the previous year and they shared in the ratio of 4:3:5:2.
How much should Bunty have earned so that his average yearly income would have been Rs 3,500?