Access time is defined as time to access one word from memory
So, it may be the answer
1 rot = 1/30 sec
In 1 rotation ---> 100 words
For 1 word ---> 1/300 rotations
So, 1 word transfer time = 1/300*1/30 sec
So, avg access time= 30 ms(seek time)+ 1/60 sec (avg rotational latency) + 1/ 9000 sec (transfer time)
= 30+16.6667+.1111 ms
= 46.78 ms(approx)