The teacher bought 25 red and blue pens. Each red pen was 1.2 yuan, and each blue pen was 1.4 yuan. The total cost was 33 yuan. How many blue pens did the teacher buy?
老师买了25支红、蓝笔，红笔每支1.2元，蓝笔每支1.4元，共花了33元，老师买了蓝笔多少支？
<gadget id="calculator">1.2 * 25</gadget>
<output>30</output>

<gadget id="calculator">33 - 30</gadget>
<output>3</output>

<gadget id="calculator">1.4 - 1.2</gadget>
<output>0.2</output>

<gadget id="calculator">3 / 0.2</gadget>
<output>15</output>

<result>15</result>