On 2 December to 5 December, an average of 53 roses were sold and from 6th December to 10 December, an average of 28 roses were sold. $324 worth of roses were sold from 11 December to 21 December. Given that a rose was sold for $3, find the average number of roses sold from 2 December to 21 December.
Number of roses sold from 11 December to 21 December
= 324 ÷ 3
= 108

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

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

Total number of roses sold
= (4 x 53) + (5 x 28) + 108
= 212 + 140 + 108
= 460

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

Average number of roses sold
= 460 ÷ 20
= 23

Answer(s): 23