A group of three stations share a 56-kbitsls pure ALOHA channel. The average bit rate transmitted from each of the three station is R1 = 7.5 kbits/s, R2 = 10 kbits/s. and R3 = 20 kbits/s. The size of each packet is 100 bits/packet. Find the normalized total traffic on the channel, the normalized throughput, the probability of successful transmission, and the arrival rate of successful packets. Assume that the arrival process is Poisson.