The phrase "a simple solution that" is correct and usable in written English.
You can use it when introducing a straightforward answer or method to a problem or situation.
Example: "After analyzing the issue, we found a simple solution that can be implemented quickly and effectively."
Alternatives: "an easy answer that" or "a straightforward approach that".
"We knew there was a simple solution that didn't involve developers or designers.
"There is not a simple solution that can be solved by public transport in a direct way," March says.
It's a nice improvisational touch, a simple solution that captures the easy practicality and loose charm of the place.
This small investment is a simple solution that has the potential to end lifetimes of unrelenting poverty.
Here is a simple solution that would help pilots and investigators determine the cause of in-flight problems.
I have a simple solution that would save the city a lot of money and end the suffering of horses: give police officers bicycles.
Maybe, instead of the pick and mix approach, there is a simpler solution that involves one dramatic step, such as shutting a digital channel – BBC3 or BBC4 – in the back of his mind.
Stepping back for a moment; given all we've thought through and discussed so far -- imagine for a moment that there was a simpler solution that we could use that would be even better than our current idea.
She agrees with Adams that the best way of dealing with the spectre of absurdity is "to find some way of ignoring it", a pleasingly simple solution that may involve drinking a Pan Galactic Gargle Blaster.
If a main concern is the stigma potential, there is a relatively simple solution that preserves both Mr. Bloomberg's interest in keeping fraud in check and Mr. Cuomo's desire to protect the feelings of food-stamp families.
Libertarianism has got a lot of the false positives that Communism had, in that it's a very simple solution that solves everything".
