A farmer bought 85kg of fertilizer in 12 bags . some are 5kg bags . the rest 10kg bags . how many 5kg bags did he buy? understand, plan, solve, look back
Answer (1)
Answer:The farmer bought 7 5kg bagsStep-by-step explanation:Let x be the number of 5 kg bags.Let y be the number of 10 kg bags.The total number of bags is thus x + y.The mass of x 5kg bags is x*(5 kg) The mass of y 10kg bags is y*(10 kg) Since the total mass of fertilizer is 85kg, We can add the above quantities and write: x*(5 kg) + y*(10 kg) = 85 kg (1)We are also told that the total number of bags is 12, so we can also write: x + y = 12 (2)=================We can use substitution to solve these equations. Rewrite the previous equation (2) as: y = 12 - xand then substitute it into the first equation (1): x*(5 kg) + y*(10 kg) = 85 kg x*(5 kg) + (12 - x)*(10 kg) = 85 kg We can cancel the kg unit: x*(5) + (12 - x)*(10) = 85 [x is defined as the number of 5 kg bags] 5x + 120 - 10x = 85 -5x = - 35 x = 7 5kg bags From (2), we know that: x + y = 12 bags Therefore: 7 bags + y = 12 bags y = 5 10kg bagsCheck:Do 5 10kg and 7 5kg bags add to 85kg of fertilizer? 50kg + 35kg = 85kg YESThe farmer bought 7 5kg bags
