It was intended that Rs. 2,820 be divided among A, B and C in the ratio of 3 : 4 : 5, but by mistake the distributions was made in the proportion of \({1\over 3}:{1\over4}:{1\over5}\). How much does A gain by the error?
1
Rs. 500
2
Rs. 495
3
Rs. 720
4
Rs. 17