The number of robberies in Springfield in 2013 is 250.
Explanation:
Here let us assume that the number of robberies in 2013 = m
Given the number of robberies in 2014 = 315
As we can see the robberies has risen by 26% .\
⇒ 26% + 100 % of Robberies in 2013 = 315
⇒ 126% of m = 315
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or, m = 250
Hence, the number of robberies in Springfield in 2013 is 250.