Astronaut uncle every 2 hours

Test center: tree planting topic: tree planting analysis: this topic can be regarded as a tree planting problem at both ends. There are 50-1 = 49 intervals from the beginning of the1call to the end of the 50th call * *, and the total elapsed time can be obtained with 49×2; According to this answer, (50- 1) × 2 = 98 (hours) A: The total time from the beginning of the 1 call to the end of the 50th call is 98 hours, which is correct. So choose: A. Comments: This question examines the problem of planting trees at both ends: interval number = number of trees planted -65438.