In a wholesale centre, ⁷₁₁ of the customers were male. There were 90 more male customers. Within five minutes, some male customers left the wholesale centre. As a result, there were ⁵₇ as many female customers as male customers. How many male customers left the wholesale centre during the five minutes?
Number of male customers = 7 u
Total number of customers = 11 u

Number of female customers
= 11 u - 7 u
= 4 u

7 u - 4 u = 90
3 u = 90

1 u = 90 ÷ 3 = 30

Number of male customers at first
= 7 u
= 7 x 30
= 210

Number of female customers
= 4 u
= 4 x 30
= 120

The number of female customers remains unchanged.
5 p = 120

1 p = 120 ÷ 5 = 24

New number of male customers
= 7 p
= 7 x 24
= 168

Number of male customers who left
= 210 - 168
= 42

Answer(s): 42