Hiram sells kites to various corporations. To maintain his business, he must sell an average of 50 kites per month. After 5 months, Hiram has sold 30, 42, 77, 90, and 52 kites in each of the 5 months. How many kites would Hiram have to sell in the 6th month for him to meet his average of 50 kites?

Average = sum of values / number of values

=> sum of values = average * number of values

average = 50

number of values = number of months = 6

=> sum of values = 50 * 6 = 300

sum of values = 30 + 42 + 77 + 90 + 52 + x = 300

Where x is the number of kites that he has to sell to meet 300 kites sold.

x = 300 - 30 - 42 - 77 - 90 - 52 = 9

Answer: he has to sell 9 kites to meet the average of 50 kites monthly.