Natasha climbs up a hill, and descends along the same way she went up. It takes her 4 hours to reach the top and 2 hours to come back down. If her average speed along the whole journey is 3.5 kilometers per hour, what was her average speed (in kilometers per hour) while climbing to the top? Choose the correct choice
A) 2.125	B) 2.375	C) 2.625	D) 2.675	E) 2.825

Rationale: "let the distance to the top be x , so the total distance traveled by natasha is 2 x . the total time is 4 + 2 = 6 hours the average speed = total distance / total time taken = 2 x / 6 = x / 3 the average speed of the complete journey is 3.5 km / hour x / 3 = 3.5 x = 10.5 km the average speed while climbing = distance / time = 10.5 / 4 = 2.625 km / h the answer is c ."
Answer: C