Step-by-step explanation: Since he can ring up 2 customers in 8 minutes, that would mean he can ring up 4 in 16 minutes. He could also ring up 6 in 24 minutes. He could do this since every two customers is 8 minutes. 4 minutes would mean he could do 1 customer and 2 minutes would be .5 customer. So, at 24 minutes he could ring 6 customers and a extra 6 minutes to 30 minutes would add 1.5 customers to a total of 7.5 customers in half an hour (30 minutes)
