Fact are facts, Watson !
“As per Inspector Lestrade, the accused house is on the bank of a river which is quarter mile wide and has current of 2 mph“. said Dr. Watson
“Don’t forget Watson, Just opposite his house, on the other bank, is victims house. The accused can swim across to his house.” Sherlock Holmes added.
“But its impossible for him to reach there in less than ten minutes”. exclaimed Dr. Watson.
“The fact are, the accused can swims at 2.5 mph in still water and his walking speed also is 2.5 mph.”
“Can he do it any faster by a combination of swimming and walking?