A train leaves Canberra for Sydney at 12 noon and another train leaves Sydney for Canberra forty minutes later. Both travel at the same constant speed, taking 3 1/2 hours to complete the journey. At what time will they pass?
+128408 The distance between the towns must be (3.5) S = (7/2)S where S is the speed that each person travels
And 40 min = 2/3 hr
Call T the time (in hrs) it takes for the first person to travel to meet the second
But the second person has traveled 40 mintues less = [ T - (2/3)] hrs when they meet
So...we have this equation
Distance traveled by first person + Distance traveled by second person = total distance between towns
So we have
S (T) + S [ T - 2/3] = (7/2)S divide through by S
T + T - 2/3 = 7/2
2T - 2/3 = 7/2 Multiply through by 6
12T - 4 = 21 add 4 to both sides
12T = 25 divide both sides by 12
T = 25/12 hrs = 2 + 1/12 hrs = 2 hr 5 min
They will pass at [ 12 + 2 hr 5 min ] = 2:05 PM
