Task: Question Answering
Input (English): Problem: a boat crossed a lake from north to east at the speed of 7 km / h, entered a river and covered twice as much distance going upstream at 6 km / h. it then turned around and stopped at the south shore of the lake. if it averaged 3.8 km / h that day, what was its approximate downstream speed ?
Options: a. 4, b. 5, c. 6, d. 7, e. 8
Output (English): e