( kindly donot give any link and donot ) explain each and every step of your answer donot use this formula tan(beta)= 
{vsin(theta)- gt }/vcos(theta):

8. A projectile is thrown in the upward direction making an angle of 60^o with the horizontal direction with a velocity of 147 ms^-1. Then, the time after which its inclination with the horizontal is 45^o, is. 
(a) 15 s               (b) 10.98 s            (c) 5.49 s               (d) 2.745 s