In a container, there are chocolate bars of 3 colours, yellow, green and black. There are 268 less black chocolate bars than green chocolate bars. The number of black chocolate bars is ¹₃ more than the yellow chocolate bars. Given that the number of black chocolate bars is 12% of the total number of chocolate bars in the container, how many less yellow chocolate bars are there than green chocolate bars?

Yellow chocolate bars	Green chocolate bars	Black chocolate bars
	1 u + 268	1 u
3x3		4x3
88%		12%
9%	79%	12%

1 + ¹₃ = ³₃ + ¹₃ = ⁴₃

Yellow chocolate bars : Purple chocolate bars = 3 : 4

The number of black chocolate bars is repeated.  Make the number of black chocolate bars the same.

4 x 3 = 12%

Total number of yellow chocolate bars and green chocolate bars in percent
= 100% - 12%
= 88%

Number of green chocolate bars in percent
= 88% - 9%
= 79%

Number of more green chocolate bars than black chocolate bars in percent
= 79% - 9%
= 67%

67% = 268

1% = 268 ÷ 67 = 4

Number of less yellow chocolate bars than green chocolate bars
= 79% - 9%
= 70%
= 70 x 4
= 280

Answer(s): 280