Build and predict when the intercept goes negative

A study relates hours of coaching ($x$) to a skills-test score ($y$). The summaries are

$\bar{x} = 15, \quad \bar{y} = 45, \quad s_x = 3, \quad s_y = 12, \quad r = 0.9.$

Predict the score after $x = 20$ hours of coaching.