In covering a distance of 90 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: Options:
A) 5 km/h
B) 8 km/h
C) 10 km/h
D) 15 km/h
E) 20 km/h
Let A's speed be X km/hr.   Then, 90/x - 90/2x = 3   45/x = 3   x = 15 km/hr.   Answer : 15 km/h
<result>D</result>
In covering a distance of 90 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: