Final answer:
To find the weight of apples sold at the farmer's market, multiply the total weight by 1/5.
Step-by-step explanation:
To find the amount of apples the farmer sold, we need to determine what fraction of the total weight is apples. We know that 4/5 of the weight is pears, so the remaining 1/5 must be apples. Since 4/5 + 1/5 equals 1, the total weight of apples and pears is equal to the weight sold at the farmer's market. Therefore, to find the weight of the apples, we can multiply the total weight by 1/5:
Total weight of apples = Total weight of mixed fruits × 1/5