Question 5
A computer store sells four types of laptop ($A,B,C,D$) and has sold a total of $2021$ units. It is known that $20$ type $A$ laptops cost as much as $7$ type $B$ laptops, $4$ type $A$ laptops cost as much as $1$ type $C$ laptop, and $4$ type $A$ laptops cost as much as $3$ type $D$ laptops. If the same amount was collected from each type, how many type $A$ laptops were sold?