A boat goes 100 km downstream in 10 hours, and 60 m upstream in 15 hours. The speed of the stream is? Choose the correct choice from the following answers: A) 3 B) 22 1 / 4 C) 22 1 / 2 D) 22 1 / 1 E) 22 1 / 3

Rationale: "100 - - - 10 ds = 10 ? - - - - 1 60 - - - - 15 us = 4 ? - - - - - 1 s = ( 10 - 4 ) / 2 = 3 kmp answer : a"
Answer: A