During a telematch, each group of students was supposed to collect as many coloured balls as possible. Each colour represented a certain point as tabulated:

Colours	Points
Silver	4
Gold	7
Blue	8

In each container, the number of silver balls was 20% more than the number of blue balls and 10% less than the number of gold balls. Given that the total possible points if the group managed to collect all the balls were 2656 points, how many balls were not silver in colour?

Silver	Gold	Blue
6x3		5x3
9x2	10x2
18 u	20 u	15 u

	Silver	Gold	Blue	Total
Number	18 u	20 u	15u
Value	4	7	8
Total value	72 u	140 u	120 u	332 u

100% + 20% = 120%
120% = ¹²⁰₁₀₀ =⁶₅

100% - 10% = 90%
90% = ⁹⁰₁₀₀ = ⁹₁₀

Total number of points collected
= 72 u + 140 u + 120 u
= 332 u

332 u = 2656

1 u = 2656 ÷ 332 = 8

Number of balls not silver in colour
= 20 u + 15 u
= 35 u
= 35 x 8
= 280

Answer: 280