Given data:
The power of a machine is
[tex]P=1200\text{ W}[/tex]The work done by the machine is
[tex]W=42000\text{ J}[/tex]Now, the formula of the power of a machine can be expressed as,
[tex]P=\frac{W}{t}[/tex]Substituting the values in the above equation, we get:
[tex]\begin{gathered} 1200\text{ W=}\frac{42000\text{ J}}{t} \\ t=\frac{42000\text{ J}}{1200\text{ W}}(\frac{1\text{ s}}{1\text{ J/W}}) \\ =35\text{ s} \end{gathered}[/tex]Thus, the time taken by the machine is 35 s.
