annika hikes at a constant rate of 12 minutes per kilometer . she has hiked 2.75 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 40 minutes . if annika continues east , then turns around and retraces her path to reach the start of the trail in exactly 40 minutes , for how many kilometers total did she hike east ?
"set up two r x t = d cases . 1 . 1 / 12 km / min x t = 2.75 from which t = 33 mins . we know total journey time now is 40 + 33 = 73 . the rate is the same ie 1 / 12 km / min . set up second r x t = d case . 1 / 12 km / min x 73 = 6.08 km now the total journey would be halved as distance would be same in each direction . 6.08 / 2 = 3.04 d ."
add(divide(subtract(divide(40, 12), 2.75), const_2), 2.75)