So we know that 125% more will attend because it's 100% of the people from last year plus an additional 25%. This when converted to a decimal would be 1.25 (divide percent by 100). Then simply multiply the number of people from last year by 1.25.
660 × 1.25 = 825
You ca mb also break it up and do the 25% separately.
660 × .25 = 165
This value would then need to be added to last years amount because it's that many people *more*.
660 + 165 = 825
