prepa

I can not understand your Question.

Si 3 kg de carne me cuestan 255 ¿cuánto pagaré por 8.5 kg?

 [If 3 kg of meat cost me 255 how much do I pay for 8.5 kg? ]

255/ 3   = x / 8.5      cross-multiplican

255 (8.5)  = 3x         dividir por 3

[ 255 (8.5)] / 3   = x  =  722.5