The table above shows the number of days worked by acertain sales representative in each of three months last year. If the number of sales calls that therepresentative made each month was proportional to the number of days worked inthat month and if the representative made a total of 168 sales calls in thethree months shown, how many sales calls did the representative make in August?
50
51
56
57
60
A was proportional to B
A和B成正比
设比例是k,20k+17k+19k=168,k=3
19k=57