Annika hikes at a constant rate of 10 minutes per kilometer. She has hiked 2.5 kilometers east from the start of a hiking trail when she realizes that she has to be back at the start of the trail in 45 minutes. If Annika continues east, then turns around and retraces her path to reach the start of the trail in exactly 45 minutes, for how many kilometers total did she hike east? Choose the correct option.
A) 3.625	B) 3.5	C) 4	D) 4.5	E) 5

Rationale: "set up two r x t = d cases . 1 . 1 / 10 km / min x t = 2.5 from which t = 25 mins . we know total journey time now is 45 + 25 = 70 the rate is the same ie 1 / 10 km / min . set up second r x t = d case . 1 / 10 km / min x 70 = 7 km now the total journey would be halved as distance would be same in each direction . 7 / 2 = 3.5 b ."
Answer: B