On 5 November to 8 November, an average of 42 marigolds were sold and from 9th November to 13 November, an average of 23 marigolds were sold. $231 worth of marigolds were sold from 14 November to 24 November. Given that a marigold was sold for $3, find the average number of marigolds sold from 5 November to 24 November.
Number of marigolds sold from 14 November to 24 November
= 231 ÷ 3
= 77

Number of days from 5 November to 8 November
= 8 - 5 + 1
= 4

Number of days from 9 November to 13 of November
= 13 - 9 + 1
= 5

Total number of marigolds sold
= (4 x 42) + (5 x 23) + 77
= 168 + 115 + 77
= 360

Number of days from 5 November to 24 November
= 24 - 5 + 1
= 20

Average number of marigolds sold
= 360 ÷ 20
= 18

Answer(s): 18