Sheelagh runs a business from London with regional headquarters located in seven cities –Jakarta, Nairobi, Prague, Ottawa, Moscow, Canberra and Hong Kong. The company also has plants in other cities shown in the table. Her senior managers at regional headquarters work from 8 am to 5.15 pm local time and constantly check their emails between these hours but are not available outside these hours. All her staff have an international time chart displayed at their place of work.
At 12 noon in London it is:
At 3 pm in London she sends an urgent email to all her senior managers at her regional headquarters.
What is the longest possible interval between the first and last of her senior managers reading the email?
A. 9 hours
B. 14 hours
C. 17 hours
D. 16 hours
E. 7 hours
Determine what they are trying to ask, and what you will need to solve it
Eliminate any non-essential information
Draw a picture, graph, or equation
In moments of high stress like exam taking, always work with the paper they give you to avoid careless mistakes.
Solve.
This question is trying to give you a sensory overload. First, let’s slow down and ignore the table, to begin with. We are given the window that the emails may be received, and we are given the time it was sent in London time.
Approach: Find a place that has just closed when the email is sent, so you are forced to wake from practically closing time till opening time (which is the largest time window possible). What do I mean by “just closed”? Well if the last email could be received by 5:15 pm, then it must be a place where the time is as close as possible to $5:15$pm but still being closed. If we now take a look at the table, you will see that we are only working with whole hours, so 6 pm will be the earliest closed place that cannot receive emails (because you sent the email at 3 pm UK time, and we are only working with whole hours).
Now that we know all of this, we can take 6pm - 3pm = 3 hour difference
So we need to find a place that is 3 hours ahead. This would be Moscow from our list because it is 3 pm in Moscow while it is 12 pm in London. This is an important step because there is a chance that there are no places exactly 3 hours ahead, maybe there are only places 4 hours ahead. 3 hours is the best case (meaning the longest time possible) but there may be another option that is just the best of the options provided.
So, our final step is taking the number of hours between 6 pm and the 8 am opening time.
The difference between 6 pm and 8 am is 14 hours.
\fcolorbox{red}{grey!30}{Therefore the answer is B, $14$ hours. }
Hi!
ok, so I get that the last of her seniors to read the email are going to do so at 8 am because they could have received the email in the non working hours (6 pm and later) and we’d have to wait till next day at 8 am for them to read it (please confirm if i got even this part correctly), but what about the first? there are seniors who are going to receive the email in the early working hours (i think earliest is 9 am winnipeg)
so between 9 am and 8 am the next day, wouldn’t that be a 23 hour long interval? given that the question is asking about the interval of her seniors reading not just receiving the email.
can someone explain this please?
First of all, the email is sent to the regional headquarters, so we eliminate all the other names as they’re useless in this case (eg. Winnipeg) because we focus on the 7 locations with HQ
Now assuming she sent that email at 3pm in London as it says - out of the 7 cities, the email would be read immediately (Ottawa and Prague) with the other cities being in out of office hours
Looking at the remaining cities - we see that Moscow,Nairobi would be at 6 pm when the email is sent - so they ‘closed’ at 5:15 pm, as theyve just closed -they’re going to have the longest interval to the next morning to read it.
If they read it from 8 am in their timezone the following morning - there is a 14 hour gap from 6 pm to 8am, which leads to B.
Thanks! great points! But I still don’t understand what 6 pm has to do with anything since the question clearly states the managers reading the email, and surely no one is reading anything at 6 pm.
No exactly, but that’s when the email is sent in their time zone - 3 pm in London is 6 pm in their time zone - but as the email can be read immediately (the shortest interval) in other offices - we count from that time until in the last person reads its ( the managers in the 6 pm time zone will be the ones that will read this email last, 8 am in their time (so they’re the longest interval)
Ok I’m getting there lol… so some managers are going to read it immediately (first is Ottawa at 10 am), and some are going to have to wait because they received the email in non working hours, the ones who will have to wait the longest are the ones in the 6 pm time zone (when the email is sent).
Now, it’ll take 14 hours for the ones who received the email after closing hours first (6 pm) to read the email at 8 am, other words the managers who are going to have to wait the longest.
But if we go back to the question, it’s asking for the
So there needs to be a difference taken here, right? In this case the first to read it is the manager in Ottawa at 10 am , and 14 hours later the manager in Moscow and Nairobi are going to read it at 8 am, and finally from 8 am to 10 am that is an additional 2 hours, which should bring us to a grand total of 14 + 2 = 16 hours.
Can you please explain where I’m going wrong?
Edit: Ok fine I think I got it now, the 14 hours isthe difference. Thanks for the explanation!
