Question 1040815
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{{{((350-280)/280)*100}}} = {{{(70/280)*100}}} = 0.25*100 = 25%.


The ratio {{{70/280}}} = 0.25 is multiplied by 100 to get percentage.


On percentage, see the lesson <A HREF=https://www.algebra.com/algebra/homework/percentage/lessons/Percentage-problems.lesson>Percentage problems</A> in this site and the lessons associated with it.