The phrase "a problem which existed" is correct and usable in written English.
You can use it when referring to an issue that was present in the past but may not be relevant anymore.
Example: "The report highlighted a problem which existed during the previous quarter, affecting our overall performance."
Alternatives: "an issue that was present" or "a challenge that occurred".
In the Muslim context, it is far easier to selectively quote self-reinforcing religious scripture and retreat into conventional paradigms; than to actually look at a problem which exists in our society and then apply your creativity, intellect, and energy to try and come up with a solution.
What Lorimar did in hopes of beating a conflict problem, which existed also between Ponderosa steakhouses and a number of McDonald's franchise associations in the merged agency, was to establish a separate agency, called USAdvertising, last October to handle Ponderosa and Quaker State.
A little California budgetary history is necessary here, to understand the scope of the problem which existed before Proposition 25 passed in 2010.
The main problem which exists in the installation of this kind of turbines is how to control and float them on water owing to the collision of turbulent waves of the sea.
For this calibration method, there is no occlusion problem which exists in those methods based on 3D reference objects.
Cognitive problems we choose to solve do not come from a neutral reservoir of problems which existed prior to the development of sciences, but we choose those which are born on the ground of a thought style imposed on us and they are usually successfully solved within its confines.
Inside a company, there are also a lot of problems which exist for several years.
There are a lot of real world problems which exist in infinite dimension spaces.
Make a plan as to how to resolve problems which exist in other areas of the world.
We consider an ad hoc network where links use CSMA protocol similar to the one provided in [22] which prevents collision among links and also resolves hidden and exposed node problems which exist in wireless networks [23].
