Class No. 1 planted 25 poplars and 15 pine trees on campus, and a total of 39 survived. Ask for the survival rate of this tree planting?
六一班在校园里种了25棵杨树，15棵松树，一共活了39棵，求这次植树的成活率？
<gadget id="calculator">25 + 15</gadget>
<output>40</output>

<gadget id="calculator">39 / 40</gadget>
<output>39/40 = around 0.975</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">(39/40) * 1</gadget>
<output>39/40 = around 0.975</output>

<result>39/40 = around 0.975</result>