15 male students and 15 female students in the fourth grade participated in the tree planting activity. Each male student planted 3 small saplings, and every 3 female students planted a small sapling. How many small saplings did they plant in total?
四年级的15位男同学和15位女同学参加了植树活动，每位男同学种下3棵小树苗，每3位女同学种下一棵小树苗，他们一共种下多少棵小树苗？
<gadget id="calculator">3 * 15</gadget>
<output>45</output>

<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<gadget id="calculator">1 * 5</gadget>
<output>5</output>

<gadget id="calculator">45 + 5</gadget>
<output>50</output>

<result>50</result>