SSC GD Constable 17 Nov 2021 Shift 3 Paper

A trader purchased 360 packets of pencils at the rate of ₹15 per packet. He sold 60% of the packets at the rate of ₹ 18 per packet and the remaining packets at the rate of ₹ 20 per packet. What is his gain percent (up to one decimal place) in this transaction ?