To reduce the time it takes to find a phone call 10 minutes/time per pay telephone numbers: 1/143/60 minutes: find the phone call 10 minutes: 10 * 2.38 = 23.8.
Can reduce the time used in finding telephone 10 minutes / time to 1 phone: wage / minutes: 143 / 60 searching telephone time 10 minutes: 10 * 2.38 = 23.8.