A person produces an average of 25 parts per day in the first 4 days, and the number of parts produced on the 5th day is 2.4 more than the average number of the previous 5 days. How many parts does this person produce on the 5th day?
某人前4天平均每天生产零件25个，第5天生产的零件比前5天的平均数还多2.4个，此人第五天生产多少个．
<gadget id="calculator">25 + 2.4</gadget>
<output>27.4</output>

<result>27.4</result>