Each evening at sunset, the lights on the London Eye Ferris Wheel are turned on. The time of the sunset in London can be modeled by the equation

s= 2.891sin(0.016d-1.183)+18.512

where s is the time of the sunset, and d is the day of the year.

a) Use the equation to determine the time of day that the sun sets on July 19th, which is day 200.

b) On how many days of the year, to the nearest whole number, will the lights be turned on at 7pm (19:00) or later?

Please show all the steps!