A total of 100 students in the sixth grade watered a small tree together. Boys each carried 2 buckets of water, and 2 girls carried 1 bucket of water. The result was a total of 110 buckets of water. How many girls are there?
六年级共有学生100人一起给小树浇水，男生每人提2桶水，女生2人提1桶水，结果共浇水110桶，女生有多少人．
<gadget id="calculator">2 * 100</gadget>
<output>200</output>

<gadget id="calculator">200 - 110</gadget>
<output>90</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 - (1/2)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">90 / (3/2)</gadget>
<output>60</output>

<result>60</result>