The TV factory planned to assemble 180 color TVs in 4.5 hours, but actually assembled 5 more sets per hour than planned. How many hours did it actually take?
电视机厂计划用4.5小时装配180台彩电，实际每小时比计划多装配5台，实际用了多少小时？
<gadget id="calculator">180 / 4.5</gadget>
<output>40</output>

<gadget id="calculator">40 + 5</gadget>
<output>45</output>

<gadget id="calculator">180 / 45</gadget>
<output>4</output>

<result>4</result>