Sentence examples for this problem was from inspiring English sources

The solution to this problem was simple.

This problem was mirrored in Sweden.

This problem was an existential dilemma for Volkswagen's engineers.

"Mathematically, this problem was solved centuries ago," he said.

This problem was to be solved at one stroke.

Looks like this problem was all Google.

This problem was shown to be undecidable.

This problem was noticed by Hesse (1966).

This problem was studied experimentally.

From this problem was born Evercam.

This problem was studied in [1].