A house decreased in value from $250,000 to $210,000.

By what percentage does it need to increase in order to
return to its original value of $250,000?

To calculate the percentage increase needed to return to the original value of $250,000, we can use the following formula:

(Original Value - New Value) / Original Value x 100%

Plugging in the values, we get:

(250,000 - 210,000) / 250,000 x 100%
= 40,000 / 250,000 x 100%
= 0.16 x 100%
= 16%

Therefore, the house needs to increase by 16% in order to return to its original value of $250,000.