I would think it is round each amount to the nearest thousand dollars.
Time used for the call to Zurich: ($5-$1.25)/$0.25=15 minutes
15minutes+3minutes=18minutes
Time used for the call to London: ($7.25-$1.25)/$0.25=24 minutes
24minutes+3minutes=27minutes
Difference between the two calls:27-18=9minutes
Answer:
In the pic
Step-by-step explanation:
If you have any questions about the way I solved it, don't hesitate to ask me in the comments below ÷)
Answer:
I think you forgot the context or image of that.