Let
Bus 1 start at time 0, at 50kmph
Bus 2 leaves 6 hrs later at 80kmph
Bus 3 leaves x hours later at 100kmph
At time t1 when Bus 1 and Bus 2 meet,
Bus 1 travelled for t1 hours
Bus 2 travelled for t1-6 hours
Since they meet, equating distances, 50t1 = 80*(t1-6)
t1 = 16
Since Bus 1 travels for 16 hours at 50kmph, distance covered = 50*16 = 800 km
At 100kmph, Bus 3 needs 800/100 = 8 hrs to cover this.
Since they meet after 16 hrs from Bus 1 start, Bus 3 must have left 16-8 = 8 hrs after Bus 1
Hence answer is 8
Bunuel
Three buses leave Riverton and travel along the same route toward Lakeview. Bus 1 leaves first and travels at a constant speed of 50 km/h. Bus 2 leaves Riverton 6 hours after Bus 1 and travels at a constant speed of 80 km/h. Bus 3 also leaves Riverton after Bus 1 and travels at a constant speed of 100 km/h. If Bus 2 and Bus 3 catch up to Bus 1 at the same time, how many hours after Bus 1 leaves does Bus 3 leave?
A. 2
B. 6
C. 8
D. 10
E. 16
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