We know that 252 kg of orasted coffee beans is 100% - 12.5% = 87.5% of the amount of unroasted beans, so we can write it down as:
252 = 87.5% of x
252 = 87.5/100 * x
252 = 875/1000x
252 = 175/200x
252 = 35/40x
252 = 7/8x / * 8 (both sides)
2016 = 7x / ÷ 7 (both sides)
x = 288 [kg]
Answer: We'll need to use 288 kg of unroasted coffee beans in order to obtain 252 kg of roasted beans.
