Question 1164379
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    x + (x-7) + 3x = 68.

    5x - 7 = 68

    5x     = 68 + 7 = 75

     x              = 75/5 = 15 phone calls.


<U>ANSWER</U>.  15 phone calls first evening;  15-7 = 8 phone calls seconf evening and  3*15 = 45 phone calls third evening.
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Solved.


You may check the answer by adding all 3 numbers in it.