The ring road is 900 centimeters long, A. Two ants in B start from point A at the same time and crawl in the same direction. A climbs 75 cm per minute and B climbs 60 cm per minute. How many minutes earlier does A return to point A than B?
环行路一圈长900厘米，甲．乙两只蚂蚁同时从A点出发，同方向爬行．甲每分爬75厘米，乙每分爬60厘米．甲比乙早多少分回到A点？
<gadget id="calculator">900 / 60</gadget>
<output>15</output>

<gadget id="calculator">900 / 75</gadget>
<output>12</output>

<gadget id="calculator">15 - 12</gadget>
<output>3</output>

<result>3</result>