A horizontal translation and a 180 rotation.
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
it's 0.4 while it may look like 4% it's actually 40% of 1
3/5 is the answer. Difference means to subtract
