Question

n a newspaper, it was reported that yearly robberies in Springfield were down 20% to 176 in 2011 from 2010. How many robberies were there in Springfield in 2010?

Answer 1

Answer: There were 220 robberies in Springfield in 2010.

Explanation:

Hi, to answer this question we have to write an equation with the information given.

Since the robberies decreased 20%, it means that 2011 are robberies are the 80% (100%-20%) of the 2010 robberies (x).

So if we multiply the yearly robberies in 2010 (x) by 0.8 (decimal form, 80/100=0.8) , we obtain the number of yearly robberies in 2011 (176).

x (0.80) = 176

Solving for x

x = 176/0.8

x = 220 robberies (2010)

Answer 2

Answer: There were 220 robberies in Springfield in 2010

Step-by-step explanation: If the robberies were reported to be down 20% and the new figure is 176, it simply means the figure 176 depicts 80% (or 0.8) of the figure from year 2010.

We shall take the figure in year 2010 as x, which is 100% (or 1.0) and year 2011 is 176 which is 80% (or 0.8). What we now have is;

176/x = 0.8

176/x = 4/5

By cross multiplication we now have;

(176 x 5)/4 = x

880/4 = x

220 = x

Therefore, there were 220 robberies in Springfield in 2010