Justin, Oscar and Chung collected stamps in the ratio of 10 : 7 : 8. After Chung gave ⁷₁₀ to Justin and Oscar, Chung had 416 less stamps than Justin. The number of stamps that Oscar had increased by 40%. How many stamps did Justin and Chung have in the end?

	Justin	Oscar	Chung
Before	10 u	7 u	8 u
Change	+ 2.8 u	+ 2.8 u	- 5.6 u
After	12.8 u	9.8 u	2.4 u

Number of stamps that Chung gave to Justin and Oscar
= ⁷₁₀ x 8 u
= 5.6 u

Number of stamps that Oscar received from Chung
= ⁴⁰₁₀₀ x 7 u
= 2.8 u

Number of stamps that Justin received from Chung
= 5.6 u - 2.8 u
= 2.8 u

Number of less stamps that Chung had less than Justin
= 12.8 u - 2.4 u 
= 10.4 u

10.4 u = 416

1 u = 416 ÷ 10.4 = 40

Number of stamps that Justin and Chung had
= 12.8 u + 2.4 u
= 15.2 u
= 15.2 x 40
= 608

Answer(s): 608