Dash Canada offers two long-distance telephone plans. Plan X costs 6.5 cents per minute for calls between

Question:

Dash Canada offers two long-distance telephone plans. Plan X costs 6.5 cents per minute for calls between 8 A.M. and 6 P.M. weekdays (business hours) and 4.5 cents per minute at other times. Plan Y costs 5.3 cents per minute any time. Above what percentage of business-hour usage will Plan Y be cheaper?