Uncle Li spends an average of 4.5 yuan in phone bills per day. He checked the phone bill balance in his phone card and found that it can be used for 16 days. If you only use 3.6 yuan per day from now on, how many days can you use these calls?
李叔叔平均每天要用4.5元话费，他查了下手机卡中的话费余额，可以用16天．如果从现在起每天只用3.6元，这些话费还可以用多少天？
<gadget id="calculator">16 / 3.6</gadget>
<output>4.444444</output>

<gadget id="calculator">4.5 * 4.444444</gadget>
<output>19.999998</output>

<result>19.999998</result>