Mark had to paint some containers. On the first day, the number of containers he painted was 40% of the number of containers that he had not painted. One week later, he painted another 55 containers. As a result, the total number of painted containers became 27 more than ²₅ of the total number of containers. How many more containers were unpainted than painted on the first day?

	Painted	Not painted	Total
Before	2x5 = 10 u	5x5 = 25 u	7x5 = 35 u
Change	+ 55	- 55
After	10 u + 55	25 u - 55	35 u
Comparing painted and not painted containers in the end	2x7 + 27 = 14 u + 27	3x7 - 27 = 21 u - 27	5x7 = 35 u

40% = ⁴⁰₁₀₀ = ²₅
Painted : Not painted = 2 : 5

The total number of containers remains unchanged. Make the total number of containers at first and in the end the same.  LCM of 7 and 5 is 35.

The number of containers painted in the end is repeated.

14 u + 27 = 10 u + 55
14 u - 10 u = 55 - 27
4 u = 28

1 u = 28 ÷ 4 = 7

Number of more containers that were not painted than painted on the first day
= 25 u - 10 u
= 15 u
= 15 x 7
= 105

Answer(s): 105