I assume you are looking for the percent increase in which case you want to find the difference between original and new, then find the percentage of the original that gives you that difference... let me show you...
400 is the new value and 350 is the original value, so we have an increase of 400 - 350 = 50
So now we find what percentage of 350 is 50.
In math "of" means ×
"is" means =
x × 350 = 50
350x = 50
x = 50/350
x = .1429
multiply by 100 to convert to percent (move decimal to the right 2 places).
.1439 × 100 = 14.29%
So the percentage of increase is 14.29%
