The distance between A and B is 205 km. One boat starts moving from A towards B in downstream at 8:15 am. After one hour, another boat starts from B towards A. Both the boats meet at 02:15 pm. If speed of first and second boat in still water is 21 km/hr and 15 km/hr respectively, then find the speed of current.
Answer & explanation
Correct answer: option 2
Let the speed of current be s km/hr
Distance covered by first boat in 1 hour = (21 + s) km
Distance between two boats becomes= 205 - (21 + s) at 09:15am
Relative speed of two boats = (21 + s) - (15 - s) = 2s + 6
(Since, the second boat will travel upstream)
Distance = Speed x time
⇒ 205 - (21 + s) = (2s + 6) x 5
⇒ 184 - s = 10s + 30
⇒ 11 s = 154
s = 14