Answer:
132 mangoes were sold
Step-by-step explanation:
Total mangoes = Total number of crates * number of mangoes in each crates
             = 28 * 36
             = 1008 mangoes
Number of mangoes repacked = Number of boxes * number of mangoes in each box
                          = 73 * 12
                          = 876 repacked mangoes
Ripe mangoes that were sold = 1008 - 876
                         = 132