In a newspaper, it was reported that yearly robberies in Springfield were up 40% to 77 in 2012 from

In a newspaper, it was reported that yearly robberies in Springfield were up 40% to 77 in 2012 from 2011. How many robberies were there in Springfield in 2011?

Let r be the number of robberies in 2011. We have:
Robberies in 2012 = Robberies in 2011 * 1.4

77 = r * 1.4

Divide each side by 1.4
r = 55