Quant Boosters  Shashank Prabhu, CAT 100 Percentiler  Set 3

18 ft of submarine's height + accounting for the 2 ft underwater torpedo means that the submarine has to sink by 20 ft. So, it will have to lose 20000 gallons. So, it will need 20000/3000 ie 20/3 minutes to go under. Distance to be travelled is 150 km. So, speed should be 150/(20/3) = 45/2 km/min or 1350 kmph.

@shashank_prabhu can we use partition method here?

@NamanJain0
Partition method is applicable for cases like dividing n identical objects among r distinguishable parts right ? How would you apply it here ?