Solving Math Problem in Getafe, Spain: 1981-2011

[LOTR]

I am having a difficulty solving a math problem and I am not sure where to begin.

Compared to the annual rainfall from 1981-2008, the 309.36 mm of rainfall in Getafe, Spain (near Madrid) in 2009 was more than 42.07% of the previous 28 years, but the 463.04 mm of rainfall in 2010 was more rainfall than 91.92% of those years.

1) Calculate the amount of rainfall needed in the 2011 season to maintain the average established from 1981-2008.2) Getafe received 293.08 mm of rain in 2011. Calculate the percentile to accurately complete the statement below.

2011 saw more rainfall than ____% of the years from 1981-2008.

3) Find the average annual rainfall from 1981-2011 to the nearest hundredth of a millimeter.

Thank you for the help in advance.

 

[jvicens]

Hello there,

I can definitely understand your frustration with this math problem. I deal with numbers and calculations every day, so I am happy to assist you with this.

First, let's break down the given information to make it easier to understand. From 1981-2008, the average annual rainfall in Getafe, Spain was 309.36 mm. In 2009, there was more rainfall than 42.07% of those years, and in 2010, there was more rainfall than 91.92% of those years.

1) To calculate the amount of rainfall needed in the 2011 season to maintain the average established from 1981-2008, we can use the following equation:

Total rainfall from 1981-2008 = (28 years) x (average annual rainfall)

Therefore, the total rainfall from 1981-2008 is 28 x 309.36 = 8652.48 mm.

To maintain this average, the total rainfall from 1981-2011 should also be 8652.48 mm.

So, the amount of rainfall needed in 2011 = 8652.48 mm - (309.36 mm + 463.04 mm) = 7880.08 mm.

Therefore, the amount of rainfall needed in 2011 to maintain the average is 7880.08 mm.

2) To find the percentile of the rainfall in 2011, we can use the following formula:

Percentile = (Number of years with less rainfall than 2011 / Total number of years) x 100

Number of years with less rainfall than 2011 = 28 (since we are comparing it to the 28 years from 1981-2008)

Total number of years = 28 + 1 (since we are including 2011)

Therefore, the percentile of the rainfall in 2011 = (28/29) x 100 = 96.55%.

This means that 2011 saw more rainfall than 96.55% of the years from 1981-2008.

3) To find the average annual rainfall from 1981-2011, we can use the following formula:

Average annual rainfall = (Total rainfall from 1981-2011) / (Number of years)

Total rainfall from 1981-2011 = 28 x 309.36 + 463