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	3
Yellow	4
Pink	6

In each container, the number of black balls was 20% more than the number of pink balls and 10% less than the number of yellow balls. Given that the total possible points if the group managed to collect all the balls were 896 points, how many balls were not black in colour?

Black	Yellow	Pink
6x3		5x3
9x2	10x2
18 u	20 u	15 u

	Black	Yellow	Pink	Total
Number	18 u	20 u	15u
Value	3	4	6
Total value	54 u	80 u	90 u	224 u

100% + 20% = 120%
120% = ¹²⁰₁₀₀ =⁶₅

100% - 10% = 90%
90% = ⁹⁰₁₀₀ = ⁹₁₀

Total number of points collected
= 54 u + 80 u + 90 u
= 224 u

224 u = 896

1 u = 896 ÷ 224 = 4

Number of balls not black in colour
= 20 u + 15 u
= 35 u
= 35 x 4
= 140

Answer: 140