10 athletes from our school participated in the 2008 "Drive the Future" Fujian Provincial Youth Vehicle Model Competition. There were 16 items in the competition. We are proud that our school has won awards for each project. Among them, projects winning the third prize account for 50% of the total number of projects, and the ratio of projects winning the first and second prizes is 3:1. How many projects in our school won the first prize?
我校有10名运动员参加2008年"驾驭未来"福建省青少年车辆模型大赛，比赛共有16个项目．值得骄傲的是，每个项目我校均获奖．其中获三等奖的项目占总项目数的50%，获一、二等奖的项目的比是3：1．我校有多少个项目获一等奖？
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">16 * (1/2) * (3/4)</gadget>
<output>6</output>

<result>6</result>