The library of Beihu Primary School newly purchased 150 fairy tale books and 150 story books each. Each fairy tale book is 16.8 yuan, and each story book is 13.2 yuan. How much did it cost to buy these books?
北湖小学图书室新购进童话书和故事书各150本．童话书每本16.8元，故事书每本13.2元．购进这些书一共需要多少钱？
<gadget id="calculator">16.8 + 13.2</gadget>
<output>30</output>

<gadget id="calculator">30 * 150</gadget>
<output>4_500</output>

<result>4_500</result>