A ball is droped from a high rise platform at t = 0 starting fro rest. After 6 seconds another ball is thrown downwards from the same platform with a speed v. The two balls meet at t = 18 s. What is the value of v ? (take g = 10 m/s2)

Question

( A ) 40 m/s
( B ) 55 m/s
( C ) 75 m/s
( D ) 60 m/s