সঠিক উত্তর হচ্ছে: 20 hours
ব্যাখ্যা: Let speed of the 1st ship is s kmph and speed of 2nd ship is (s + 10) kmph.\nLet 2nd ship takes time t to cover the distance 300 km then 1st ship takes (t + 8) hours.\n\nAs distance is constant, we have,\ns/(s+10)=t/(t+8)\nOr, st + 8s = st + 10t\nOr, 8s = 10t\n\nIf the slower ship took 20 hours (option D) the faster ship would take 12 hours and their respective speeds would be 15 and 25 kmph.