A man whose mass is 50 kg moves up 15 steps each of height of 15 cm in 45 seconds of time. What is the power used in climbing those stairs? Take g = 10 m/s²

A man whose mass is $50\mathit{ kg}$ moves up $15$ steps each of height of $15\mathit{ cm}$ in $45\mathit{ seconds}$ of time. The power used in climbing the stairs is,$\mathit{ P}=25\mathit{ W}$.
In general, power is given by $\mathrm{P}=\mathrm{Work} / \mathrm{Time}$.
$\Rightarrow \mathrm{P}=\mathrm{W}/\mathrm{t}$
Height of the staircase, $\mathrm{h}=15\times 0.15$
$\Rightarrow \mathrm{h}=2.25 \mathrm{m}$
Time, $\mathrm{t}=45 \mathrm{s}$
Therefore,
$\mathrm{P}=\mathrm{W}/\mathrm{t}$
$\Rightarrow \mathrm{P}=\mathrm{mgh}/\mathrm{t}$
$\Rightarrow \mathrm{P}=(50\times 10\times 2.25)/45$
$\Rightarrow \mathrm{P}=25 \mathrm{W}$