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

Colours	Points
Gold	2
Black	4
Silver	5

In each container, the number of gold marbles was 40% more than the number of silver marbles and 90% less than the number of black marbles. Given that the total possible points if the group managed to collect all the marbles were 957 points, how many marbles were not gold in colour?

Gold	Black	Silver
7x1		5x1
1x7	10x7
7 u	70 u	5 u

	Gold	Black	Silver	Total
Number	7 u	70 u	5u
Value	2	4	5
Total value	14 u	280 u	25 u	319 u

100% + 40% = 140%
140% = ¹⁴⁰₁₀₀ =⁷₅

100% - 90% = 10%
10% = ¹⁰₁₀₀ = ¹₁₀

Total number of points collected
= 14 u + 280 u + 25 u
= 319 u

319 u = 957

1 u = 957 ÷ 319 = 3

Number of marbles not black in colour
= 7 u + 5 u
= 12 u
= 12 x 3
= 36

Answer: 36