Calculus
{
name: "Calculus",
isFirstTurn: true,
run: (scores) => {
let ret = this.isFirstTurn ? 70 : (100 + (average(scores)) * 0.8) / 2;
this.isFirstTurn = false;
return ret;
}
}
Assuming the average is constant and my score is higher than that, the maximum value of \$x(100-\left|0.8 \times avg - x\right|)\$ is reached at \$x=(100+0.8\times avg)\div 2\$. Deliberately ignores the first turn input (which is totally random and cannot be trusted for any purpose).