the first number of a sequence is 200. every number of the sequence after the first is 100 less than twice the preceding number. what is the 5th number of the sequence

Answer 1

t1 = 200
t2 = 2t1 -100 = 2(200) - 100 = 300
t3 = 2t2 - 100 = 2(300) - 100 = 500
t4 = ...
..
t6 = 2t5 - 100 = ...

(you should get 3300)

Answer 2

oops, went too far, only had to go to t5

how about 1700 ?