gmat620 wrote:

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.

Yeah friends, I just solved it completely to know whether the info is sufficient. It took me nearly 3 minutes. I am horrified. Can this be solved within 2 mins through any formula or expression ? Please-please-please tell me. I am dying to know.

Thanks in advance.

Question stem says - nth term =2* (n-1)th term +1

fifth term =?

1) first term = 1

second term = 2*first term+1

and so on.... you can find fifth term using the above formula but you don't really have to calculate.

SUFFICIENT

2) sixth term - fifth term = 32

sixth term = 2* (fifth term) +1

you can find fifth term here. SUFFICIENT

answer is 'D'