A6 If we add the first 12 multiples of a number, we get a sum of 1014. These are the multiples of the number:
(A) 2
(B) 3
(C) 6
(D) 12
(E) 13
A6. We assume that $a_{1}$ and $d$ are equal because we are talking about multiples of the same number. We use the formula for the sum $s_{n}=\frac{n}{2}\left(2 a_{1}+(n-1) d\right)$. We substitute $1014=\frac{12}{2}(2 \cdot d+11 d)$ from which we calculate $d=13$.

## Block B