Answer: There are 3 DVD and 5 padded mailing envelopes.
Step-by-step explanation:
Since we have given that
Number of DVD cases are sold = 20
Number of padded mailing envelopes = 12
We need to find the least number of cases and envelopes.
L.C.M. of 20 and 12 = 60
Minimum number of DVD cases is given by

Minimum number of padded mailing envelopes is given by

Hence, there are 3 DVD and 5 padded mailing envelopes.