12. In a sequence of numbers in which each term after the first term is 1 more than twice the preceding term, what is the fifth term?
(1) The first term is 1.
(2) The sixth term minus the fifth term is 32.
Hi,
I thoght the question is x, 2x+1, 2(2x+1)+1, ..... and chose D), but the correct answer is B) -- Can anyone please explain??
test 13 #12
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I agree with you on D...Seems like (1) allows you to construct the sequence, since a1 = 1 we have
1, 3, 7, 15, 31, ..... and a5 = 31
(2) gives us
a6 - a5 = 32
2a5 + 1 - a5 = 32
a5 = 31
So, I agree that each alone is sufficient, but maybe I am missing something as to why (1) isn't.
1, 3, 7, 15, 31, ..... and a5 = 31
(2) gives us
a6 - a5 = 32
2a5 + 1 - a5 = 32
a5 = 31
So, I agree that each alone is sufficient, but maybe I am missing something as to why (1) isn't.