$\Rightarrow$ distance covered in time $\mathrm{t}=\frac{\mathrm{T}}{4}=\mathrm{A}$
$\Rightarrow$ average speed $=\frac{A}{T / 4}=\frac{4 A}{T}$

$x = 3\,sin\, 20\pi t + 4\, cos\, 20\pi t$ ,
where $x$ is in $cms$ and $t$ is in $seconds$ . The amplitude is ..... $cm$
