Motion In A Straight Line

A ball is thrown vertically upward with an initial velocity of \(150 \mathrm{~m} / \mathrm{s}\). The ratio of velocity after \(3 \mathrm{~s}\) and \(5 \mathrm{~s}\) is \(\frac{x+1}{x}\). The value of \(x\) is ___________.

\(\left\{\right.\) take, \(\left.g=10 \mathrm{~m} / \mathrm{s}^{2}\right\}\)