Question #4d5f3

1 Answer
Dec 24, 2017

[Q1] #1# hour
[Q2] The destination is #3# hours behind Sydney.
[Q3] Jakarta, Indonesia

Explanation:

#color(red)"Note: I didn't take the international date line(IDL)"# #color(red)"into consideration. My answer may be wrong."#
If so, I'll be happy to correct the errors.

I assume that the outward and homeward journeys take the same time.
Let #x# the time difference between Sydney and that city.

In the local time at Sydney:
[Outward] Sydney #10# am ⇒ the destination #(2+x)# pm
[Homeward] The destination #(12+x)# pm ⇒ Sydney #10# pm

Then, the outward trip takes #4+x# hours and the homeward trip takes #-2-x# hours.
#4+x=-2-x#
#2x=-6#
#x=-3#

So, it takes #4+(-3)=1# hour from Sydney to that city, and the time at that city is #3# hours behind Sydney.

Note: I didn't take the international date line(IDL) into consideration.

Sydney is situated at about longitude #150# degrees East. So, the destination is at long. #150-15*3=105# degrees East. One of the city at that longitude is Jakarta.
http://latitudelongitude.org/id/jakarta/