The first flight out of Phoenix airport had a late departure. If the next three flights departed on-time, how many subsequent flights need to depart from Phoenix on-time, for the airport's on-time departure rate to be higher than 60%?	Choose one.
A) 5 B) 4 C) 6 D) 8 E) 7
We need on-time departure rate to be higher than 6/10, so it should be at least 7/11, which means that 7 out of 11 flights must depart on time. Since for now 3 out of 4 flights departed on time then  7-3= 
<gadget id="calculator"> 7-3</gadget>
<output>4</output>
4 subsequent flights need to depart on-time.   Answer: 4
<result>B</result>
The first flight out of Phoenix airport had a late departure. If the next three flights departed on-time, how many subsequent flights need to depart from Phoenix on-time, for the airport's on-time departure rate to be higher than 60%?