A fair fare. Three strangers, Bob, Mary, and Ivan, meet at a taxi stand and decide to share a cab to cut down the cost. Each has
a different destination, but all the destinations are on the highway leading from the airport, so no circuitous driving is required. Bob's destination is 10 miles away, Mary's is 20 miles, and Ivan's is 30 miles. The taxi costs $2.10 per mile including the tip, regardless of the number of passengers. How much should each person pay?
