In​ 2009, a diabetic express company charged ​$38.85 for a vial of type A insulin and ​$30.34 for a vial of type B insulin. If a total of ​$1695.71 was collected for 50 vials of​ insulin, how many vials of each type were​ sold? The number of vials of type A insulin sold were ___ and the number of vials of type B insulin sold were

The number of vials of type A insulin sold were _21__ and the number of vials of type B insulin sold were __29__.

Step-by-step explanation:

Let a = number of type A vials.

Let b = number of type B vials.

38.85a + 30.34b = 1695.71

a + b = 50

            38.85a + 30.34b = 1695.71

(+)        -38.85a - 38.85b = -1942.50

                               -8.51b = -246.79

b = 29

a + b = 50

a + 29 = 50

a = 21

The number of vials of type A insulin sold were _21__ and the number of vials of type B insulin sold were __29__.