Question

One month, Diane worked 6 hours more than Elle. Together they worked 20 hours. How many hours did Diane work? How many hours did Elle work?​

Answer 1

D = E + 6
D + E = 20
Plug in the first one in the second one.
E + 6 + E = 20
2E + 6 = 20
2E = 14
E = 7
D = 13