A worker can load one truck in 6 hours. A second worker can load the same truck in 8 hours. If both workers load one truck simultaneously while maintaining their constant rates, approximately how long, in hours, will it take them to fill one truck? Answers:
A) 2.6
B) 2.8
C) 3.0
D) 3.2
E) 3.4

Rationale: "the workers fill the truck at a rate of 1 / 6 + 1 / 8 = 14 / 48 = 7 / 24 of the truck per hour . then the time to fill one truck is 24 / 7 which is about 3.4 hours . the answer is e ."
Answer: E