The length of a rectangle is a +0.5. The width of the rectangle is 2a + 11. If the perimeter is 47 inches, what's the value of a?

On the first of each month, shelly runs a 5k race. she keeps track of her times to track her progress. her time in minutes is recorded in the table: jan 40.55 july 35.38 feb 41.51 aug 37.48 mar 42.01 sept 40.87 apr 38.76 oct 48.32 may 36.32 nov 41.59 june 34.28 dec 42.71 determine the difference between the mean of the data, including the outlier and excluding the outlier. round to the hundredths place. 39.98 39.22 0.76 1.21

Write the fraction 9/50 as a decimal if needed round to the nearest hundredth

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.