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

Colours	Points
Black	4
Brown	5
Yellow	6

In each container, the number of black marbles was 80% more than the number of yellow marbles and 70% less than the number of brown marbles. Given that the total possible points if the group managed to collect all the marbles were 864 points, how many marbles were not black in colour?

Black	Brown	Yellow
9x1		5x1
3x3	10x3
9 u	30 u	5 u

	Black	Brown	Yellow	Total
Number	9 u	30 u	5u
Value	4	5	6
Total value	36 u	150 u	30 u	216 u

100% + 80% = 180%
180% = ¹⁸⁰₁₀₀ =⁹₅

100% - 70% = 30%
30% = ³⁰₁₀₀ = ³₁₀

Total number of points collected
= 36 u + 150 u + 30 u
= 216 u

216 u = 864

1 u = 864 ÷ 216 = 4

Number of marbles not black in colour
= 30 u + 5 u
= 35 u
= 35 x 4
= 140

Answer: 140