Ahmad had to paint some containers. On the first day, the number of containers he painted was 30% of the number of containers that he had not painted. One week later, he painted another 253 containers. As a result, the total number of painted containers became 13 more than ³₅ of the total number of containers. How many more containers were unpainted than painted on the first day?

	Painted	Not painted	Total
Before	3x5 = 15 u	10x5 = 50 u	13x5 = 65 u
Change	+ 253	- 253
After	15 u + 253	50 u - 253	65 u
Comparing painted and not painted containers in the end	3x13 + 13 = 39 u + 13	2x13 - 13 = 26 u - 13	5x13 = 65 u

30% = ³⁰₁₀₀ = ³₁₀
Painted : Not painted = 3 : 10

The total number of containers remains unchanged. Make the total number of containers at first and in the end the same.  LCM of 13 and 5 is 65.

The number of containers painted in the end is repeated.

39 u + 13 = 15 u + 253
39 u - 15 u = 253 - 13
24 u = 240

1 u = 240 ÷ 24 = 10

Number of more containers that were not painted than painted on the first day
= 50 u - 15 u
= 35 u
= 35 x 10
= 350

Answer(s): 350