A ball is dropped from a high rise platform at t = 0 starting from 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)
1
60 m/s
2
75 m/s
3
55 m/s
4
40 m/s
5
None of the above/More than one of the above.