A biker covered half the distance between two towns in 2 hr 30 min. After that he increased his speed by 2 km/hr. He covered the second half of the distance in 2 hr 20 min. Find the distance between the two towns and the initial speed of the biker.
Choose one
A) 140
B) 260
C) 320
D) 480
E) 500
Let x km/hr be the initial speed of the biker, then his speed during the second part of the trip is x + 2 km/hr. Half the distance between two cities equals 2*30/60⋅x km and 2*20/60⋅(x+2) km. From the equation: 2*30/60⋅x=2*20/60⋅(x+2) we get x=28 km/hr.   The intial speed of the biker is 28 km/h.   Half the distance between the two towns is   2h30min×28=2.5×28=70.   So the distance is 2×70=140 km
<result>A</result>
A biker covered half the distance between two towns in 2 hr 30 min. After that he increased his speed by 2 km/hr. He covered the second half of the distance in 2 hr 20 min. Find the distance between the two towns and the initial speed of the biker.