What is the probability of flipping a coin 5 times and getting heads the first time and tails the next 3 times?
任意掷5次硬币，第1次正面朝上，接着3次反面朝上，第5次正面朝上的可能性为多少
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>