Q178
ArithmeticNumber Series & Progressions
Let x1, x2, ..., x100 be 100 numbers such that x_i + x_(i+1) = 100 for all i. If x_10 = 1, then the value of x1 is
- a.100
- b.99
- c.101
- d.1
Answer: (B) 99
Since consecutive terms alternate to sum to 100, x_10 = 1 forces even-indexed terms to be 1 and odd-indexed terms to be 99, so working back to x1 (odd index) gives x1 = 99.