Pg 324 (336) - Q11
They're saying that the first number in a sequence of ten numbers; they didn't say integers, and they didn't say digits; they said numbers. Numbers can be fractions or decimals. So, the sum of 10 numbers in a sequence could be anything; there is no way of knowing what type of sequence you're in because you don't know about the numbers at all. Therefore, the answer here is D.