A body travels 200 cm in the first two second and 220 cm in the next 4 sec with deceleration. The velocity of the body at the end of the 7th second is

200=u×2−12a(2)2Or u - a = 100….(1)(200+220)=u(2+4)−12a(2+4)2or u -3 a = 70 ….(2)Solving eqs. (1) and (2), we get a = 15 cm/s2 and u = 115 cm/sec Further V = u -at = 115 -15 x 7 = 10 cm/sec