On Sunday, mother has to do the following housework: it takes 20 minutes to clean the glass, 15 minutes to clean the kitchen, 30 minutes to wash clothes with a fully automatic washing machine, and 10 minutes to dry them. How many minutes does it take for mother to finish these things at least.
星期天妈妈要做以下家务事：擦玻璃要20分钟，收拾厨房要15分钟，用全自动洗衣机洗衣服需要30分钟，晾衣服要10分钟．妈妈做完这些事最少需要多少分钟．
<gadget id="calculator">20 + 15</gadget>
<output>35</output>

<gadget id="calculator">35 + 10</gadget>
<output>45</output>

<result>45</result>