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
Yellow	2
White	4
Silver	7

In each container, the number of yellow balls was 20% more than the number of silver balls and 10% less than the number of white balls. Given that the total possible points if the group managed to collect all the balls were 1768 points, how many balls were not yellow in colour?

Yellow	White	Silver
6x3		5x3
9x2	10x2
18 u	20 u	15 u

	Yellow	White	Silver	Total
Number	18 u	20 u	15u
Value	2	4	7
Total value	36 u	80 u	105 u	221 u

100% + 20% = 120%
120% = ¹²⁰₁₀₀ =⁶₅

100% - 10% = 90%
90% = ⁹⁰₁₀₀ = ⁹₁₀

Total number of points collected
= 36 u + 80 u + 105 u
= 221 u

221 u = 1768

1 u = 1768 ÷ 221 = 8

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

Answer: 280