Major and Minor triad

As shown above, the $12$ keys on the piano are denoted as $a_1,a_2,\cdots,a_{12}$ respectively from left to right.

Let $1 \leq i < j < k \leq 12$ , if $k-j=3, j-i=4$ , then $(a_i,a_j,a_k)$ is a Major triad.

If $k-j=4, j-i=3$ , then $(a_i,a_j,a_k)$ is a Minor triad.

Then what's the total number of Major triad and Minor triad produced using these $12$ keys?

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Source: Gaokao 2020, II