I think it is b hope it helps
First find average
(5+5+5+5+7+9)/6=6
now see how much they each are differnt
5 to 6 is 1
5 to 6 is 1
5 to 6 is 1
5 to 6 is 1
7 to 6 is 1
9 to 6 is 3
average those
(1+1+1+1+1+3)/6=8/6=4/3=1.333
answer is 1.33
150,000
100,000 < 150,000 < 200,000
First differences are -9, +18, -8, +16, suggesting that the next ones will be -7, +14.
Hence, the next two terms might be expected to be 13, 27.
1 2/3 is the same as 5/3, so the reciprocal is 3/5
