Answer :
The time at Sydney when Dan rings his friend is 1 : 30 am (option B).
What is the time at Sydney?
The first step is determine the time difference between London and Sydney.
Time difference = time at Sydney - time at London
( 12 + 10pm) - 12pm
22pm - 12pm = 10 hours
The second step is to add the time difference to the time it was when Dan rang.
15 : 30 pm + 10pm = 25 : 30
We know that there are only 24 hours in day, so subtract 24 hours from 25 : 30
25 : 30 - 24 = 1 : 30 am
To learn more about how to calculate time, please check: https://brainly.com/question/26290873
#SPJ1