Answer:
[tex]\large \boxed{\text{100 N}}[/tex]
Explanation:
The mechanical advantage (MA) is the ratio of the output force to the applied force.
[tex]\begin{array}{rcl}MA &=& \dfrac{F_{\text{o}}}{F_{\text{a}}}\\\\6 &=& \dfrac{\text{600 N}}{F_{\text{a}}}\\\\6F_{\text{a}} & = &\text{600 N}\\\end{array}\\[/tex]
[tex]\begin{array}{rcl}F_{\text{a}} & = & \dfrac{\text{600 N}}{6}\\\\& = & \textbf{100 N}\\\end{array}\\[/tex]
The input force required is 100 N.