Lily divides $50$ postcards into $5$ envelopes. One week after Lily has already divided the postcards, her friends give her some other postcards, and then Lily divides those new postcards into another $2$ envelopes. Each envelope has the same number of postcards. How many postcards in total are there? 
Overseas Competition->Knowledge Point->Word Problem Modules->Unitary Method Problems->Finding the Unit Rate and then the Total Value