Problem Solving

Sam observed that when it is 10am in City A it is 4pm on the previous day in City B.
Sam boards a flight from City A that takes off at 3am City A local time and arrives in City B at 7am City B local time.
On the return leg of the journey from City B to City A the plane flew at double the speed and took half the time. If Sam boarded the plane at 3am City B local time at what time would he arrive in City A. (ignore the day on which the flight will arrive in City A)
(A)4am City A time
(B) 8pm City A time
(C) 7 am City A time
(D)None of the other options

sgr21 wrote:Sam observed that when it is 10am in City A it is 4pm on the previous day in City B.
Sam boards a flight from City A that takes off at 3am City A local time and arrives in City B at 7am City B local time.
On the return leg of the journey from City B to City A the plane flew at double the speed and took half the time. If Sam boarded the plane at 3am City B local time at what time would he arrive in City A. (ignore the day on which the flight will arrive in City A)
(A)4am City A time
(B) 8pm City A time
(C) 7 am City A time
(D)None of the other options

City A to City B:
10am City A (Day 2) <=> 4pm City B (Day 1)
3am City A (Day 2) <=> 9am City B (Day 1)
1am City A (Day 3) <=> 7am City B (Day 2)
Journey time = 22 hours

City B to City A:
Return journey time = 11 hours
9pm City A (Day 3) <=> 3am City B (Day 3)
So it would arrive in City A at (9pm + 11 hours) = 8am
Choose D

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