Albert had to paint some boxes. On the first day, the number of boxes he painted was 10% of the number of boxes that he had not painted. One week later, he painted another 145 boxes. As a result, the total number of painted boxes became 28 more than ¹₂ of the total number of boxes. How many more boxes were unpainted than painted on the first day?

	Painted	Not painted	Total
Before	1x2 = 2 u	10x2 = 20 u	11x2 = 22 u
Change	+ 145	- 145
After	2 u + 145	20 u - 145	22 u
Comparing painted and not painted boxes in the end	1x11 + 28 = 11 u + 28	1x11 - 28 = 11 u - 28	2x11 = 22 u

10% = ¹⁰₁₀₀ = ¹₁₀
Painted : Not painted = 1 : 10

The total number of boxes remains unchanged. Make the total number of boxes at first and in the end the same.  LCM of 11 and 2 is 22.

The number of boxes painted in the end is repeated.

11 u + 28 = 2 u + 145
11 u - 2 u = 145 - 28
9 u = 117

1 u = 117 ÷ 9 = 13

Number of more boxes that were not painted than painted on the first day
= 20 u - 2 u
= 18 u
= 18 x 13
= 234

Answer(s): 234