On 2 September to 5 September, an average of 52 lilies were sold and from 6th September to 10 September, an average of 22 lilies were sold. $284 worth of lilies were sold from 11 September to 21 September. Given that a lily was sold for $2, find the average number of lilies sold from 2 September to 21 September.
Number of lilies sold from 11 September to 21 September
= 284 ÷ 2
= 142

Number of days from 2 September to 5 September
= 5 - 2 + 1
= 4

Number of days from 6 September to 10 of September
= 10 - 6 + 1
= 5

Total number of lilies sold
= (4 x 52) + (5 x 22) + 142
= 208 + 110 + 142
= 460

Number of days from 2 September to 21 September
= 21 - 2 + 1
= 20

Average number of lilies sold
= 460 ÷ 20
= 23

Answer(s): 23