In covering a distance of 40 km, A takes 2 hours more than B. If A doubles his speed, then he would take 1 hour less than B. A's speed is:
Choose the correct choice:  A) 5 km/h  B) 6.7 km/h  C) 10 km/h  D) 15 km/h  E) 20 km/h
Let A's speed be X km/hr.   Then, 40/x - 40/2x = 3   20/x = 3   x = 6.7 km/hr.   Answer : 6.7 km/h
<result>B</result>
In covering a distance of 40 km, A takes 2 hours more than B. If A doubles his speed, then he would take 1 hour less than B. A's speed is: