# How to find proportion of tennis players serves based on bell shaped distribution?

**Question description**

At the U.S. Open Tennis Championship a statistician keeps track of every serve that a player hits during the tournament. The statistician reported that the mean serve speed of a particular player was 101 miles per hour (mph) and the standard deviation of the serve speeds was 10 mph. Assume that the statistician also gave us the information that the distribution of serve speeds was mound-shaped and symmetric. Find the percentage of serves that were hit with a speed between 121 and 131 mph.

Answer choices A) 131 B) .047 C) .0235 D) .997

I know the answer is C, because I have the answer key, but I'd like to know HOW to get that answer!

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