1. The problem states that there are 40 erasers in one packet. 2. We received 128 eraser packets. 3. The price per packet is 280 rupees, but this is not needed to find how many packets are in one carton. 4. The question asks: How many packets are in one carton? Since the problem states "we received 128 eraser packet per packet price is 280 rupees," it seems the 128 packets are the total received, but the number of packets in one carton is not directly given. If the question is to find how many packets are in one carton, and if 128 packets are received in total, then the number of packets in one carton is 128 (assuming one carton contains all packets received). Therefore, the answer is: $$\text{Number of packets in one carton} = 128$$ If the question meant something else, please clarify.