Bunuel wrote:
If T is a list of consecutive integers in increasing order, what is the sum of integers in T?
(1) The difference between the last integer in T and the first integer in T is 100. This implies that there are 101 integers in the list. T could be any list of 101 consecutive integers. For example, {0, 1, 2, ..., 100} or {1, 2, 3, ..., 101}. Not sufficient.
(2) The fourth integer in T is -6. This implies that the first integer is -9. We don't know how many integers are there in the list, hence cannot get the sum. Not sufficient.
(1)+(2) We know that the first integer is -9 and that there are total of 101 integers in the list: T = {-9, -8, -7, -6, ..., 91}. We can get the sum. Sufficient.
Answer: C.
Hope it's clear.
Hi Burnel, why is the first integer -9?