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

Colours	Points
Black	4
Gold	6
White	7

In each container, the number of black balls was 80% more than the number of white balls and 70% less than the number of gold balls. Given that the total possible points if the group managed to collect all the balls were 1757 points, how many balls were not black in colour?

Black	Gold	White
9x1		5x1
3x3	10x3
9 u	30 u	5 u

	Black	Gold	White	Total
Number	9 u	30 u	5u
Value	4	6	7
Total value	36 u	180 u	35 u	251 u

100% + 80% = 180%
180% = ¹⁸⁰₁₀₀ =⁹₅

100% - 70% = 30%
30% = ³⁰₁₀₀ = ³₁₀

Total number of points collected
= 36 u + 180 u + 35 u
= 251 u

251 u = 1757

1 u = 1757 ÷ 251 = 7

Number of balls not black in colour
= 30 u + 5 u
= 35 u
= 35 x 7
= 245

Answer: 245