math problem, I am stuck please help! thank you!?

Old Faithful is a famous geyser at Yellowstone National Park. The mean duration of its eruptions is 3.32 minutes with a standard deviation of 1.09 minutes. What can we say about the percentage of eruptions which lasted between 1.14 and 5.5 minutes.?

i have tried to solve but i do not understand, please help thank you!

To do this problem, you should have a reference sheet with a chart similar to the one I put a link of at the bottom of this answer.
On the chart, the symbol in the middle means the mean. When you move one number to the left or right, you are moving one standard deviation away from the mean. \
You know your mean is 3.32 and your standard deviation is 1.09, so just keep adding and subtracting 1.09 from 3.32 until you get 1.14 and 5.5.

To get from 3.32 to 5.5, you add 1.09 twice, or you go two standard deviations from the mean.
To get from 3.32 to 1.14 you subtract 1.09, or go negative two standard deviations from the mean.

So now you know you are going from -2 standard deviations to +2 standard deviations. Go to the chart I attached and add all the percentages between -2 and +2 to get 95.4

Hope this helps!

Here is the chart you need to use http://kermittheblog.files.wordpress.com/2007/05/normal.jpg