Rahul deposited an amount ‘Q’ in a plan A and earned Rs. 300 as interest after one year. He then added Rs. 600 to the amount and re-invested the entire sum in the same plan A for another year. After the second year, he received Rs. 5280 as the total amount. Find the interest earned if the amount ‘Q’ was invested in a different scheme B offering 10% compound interest per annum for 2 years.