The store sells two baskets of apples with the same unit price, the first basket is 20 kg, the second basket is 25 kg, and the price of the second basket is 12.5 yuan more than the first basket. What is the average price of an apple per kilogram?
商店卖出两筐单价相同的苹果，第一筐20千克，第二筐25千克，第二筐比第一筐多卖12.5元．平均每千克苹果的价钱是多少元？
<gadget id="calculator">25 - 20</gadget>
<output>5</output>

<gadget id="calculator">12.5 / 5</gadget>
<output>2.5</output>

<result>2.5</result>