Sixth grade math problem: Mom bought 4 kilograms of apples and 5 kilograms of pears, and the money spent on buying these two fruits is equal. What is the unit price ratio between apples and pears? ② The unit price of apples is 3.5 yuan/kg. What is the unit price of pears?

Let the unit prices of apples and pears be X and Y yuan/kg respectively.

Then 4x=5y, then x:y=5:4.

② The unit price of apples is 3.5 yuan/kg, and that of pears is y=4/5*3.5=2.8 (yuan/kg).