Data Sufficiency

Find the fourth consecutive even number:
(I) The sum of the last two numbers is 30
(II) The sum of the first two numbers is 22

IMO D

Let the 4 consecutive numbers be a, a+2, a+4, a+6

Stmt1: Sum of last 2 numbers, i.e. (a+4) + (a+6) = 30 ==> 2a+10 = 30 ==> a = 10. So, the fourth even number is a+6 ==> 16. Sufficient.

Stmt2: Sum of first 2 numbers, i.e. a + (a+2) = 22 ==> 2a+2 = 22 ==> a = 10. So, the fourth even number is a+6 ==> 16. Sufficient.

I think the answer is B.

1) We don't know no. of item in the sequence, so we couldn't calulate the fouth item.

Insufficient

2) The sum of the first two numbers is 22,
10+12=22

the forth item is 16

Sufficient

IMO B

Vemuri wrote:IMO D

Let the 4 consecutive numbers be a, a+2, a+4, a+6

Stmt1: Sum of last 2 numbers, i.e. (a+4) + (a+6) = 30 ==> 2a+10 = 30 ==> a = 10. So, the fourth even number is a+6 ==> 16. Sufficient.

Stmt2: Sum of first 2 numbers, i.e. a + (a+2) = 22 ==> 2a+2 = 22 ==> a = 10. So, the fourth even number is a+6 ==> 16. Sufficient.

please explain, how do we know the no. of numbers are there in the sequence.

ketkoag wrote: please explain, how do we know the no. of numbers are there in the sequence.

I am making a lot of silly mistakes today. My bad. I agree with kic883's explanation. The answer should be B.