n a series of numbers , the next number is formed by adding 1 to the sum of the previous numbers, and the 10th number is 1280. Then what is the first number in the series? (series will be like this x , x+1, (x+(x+1))+1,....... )  Select the correct option:  A) 2  B) 4  C) 5  D) 7  E) 9
Answer: Option B   Sol.   The given series is x, x + 1, 2x + 2, 4x + 4 ......   If you observe the pattern here, the coefficient of x + 1 is in the powers of 2. So 4th term has a power of 2, 5th term has a power of 3... 10th term has a power of 8. So tenth term would be 2828(x + 1)   = 256(x+1).   Given 256(x+1) = 1280   x = 4.   Answer:4
<result>B</result>
n a series of numbers , the next number is formed by adding 1 to the sum of the previous numbers, and the 10th number is 1280. Then what is the first number in the series? (series will be like this x , x+1, (x+(x+1))+1,....... )