Answer: 77 suits
Explanation:
Let sales of this month = x
Sales for last 4 months = 92, 28, 83, 75
Average = Sum of Observation ÷ No of Observation
Now, we can form an equation
(92+28 +83+75+x) ÷ 5 =71
(92+28 +83+75+x) = 71 × 5
278 + x = 355
x = 355 - 278
x = 77