Xavier, Sean and Colin collected buttons in the ratio of 10 : 4 : 7. After Colin gave ⁷₁₀ to Xavier and Sean, Colin had 384 less buttons than Xavier. The number of buttons that Sean had increased by 80%. How many buttons did Xavier and Colin have in the end?

	Xavier	Sean	Colin
Before	10 u	4 u	7 u
Change	+ 1.7 u	+ 3.2 u	- 4.9 u
After	11.7 u	7.2 u	2.1 u

Number of buttons that Colin gave to Xavier and Sean
= ⁷₁₀ x 7 u
= 4.9 u

Number of buttons that Sean received from Colin
= ⁸⁰₁₀₀ x 4 u
= 3.2 u

Number of buttons that Xavier received from Colin
= 4.9 u - 3.2 u
= 1.7 u

Number of less buttons that Colin had less than Xavier
= 11.7 u - 2.1 u 
= 9.6 u

9.6 u = 384

1 u = 384 ÷ 9.6 = 40

Number of buttons that Xavier and Colin had
= 11.7 u + 2.1 u
= 13.8 u
= 13.8 x 40
= 552

Answer(s): 552