The school held a "June • 1st" celebration party and bought some balloons. Among them, there are 120 red ones, and the yellow balloons are red (3/4) and blue at the same time (5/7). How many blue balloons did the school buy?
学校召开"六•一"庆祝会，买来一些气球．其中红色的有120个，黄色气球是红色的(3/4)，同时又是蓝色的(5/7)．学校买来蓝色气球多少个？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(3/4) / (5/7)</gadget>
<output>21/20 = around 1.05</output>

<gadget id="calculator">120 * (21/20)</gadget>
<output>126</output>

<result>126</result>