Energy possessed by a photon is given by

$E=hf=\frac{hc}{\lambda }$

If power of each bulb is $P$ then energy given out in $\mathrm{time\; t}$ equal to $Pt.$ Let the number of photons be $n$, then

$n=\frac{Pt}{E}=\frac{Pt}{(hc/\lambda )}=\frac{Pt\lambda }{hc}$

For red light, $n_R=\frac{Pt{\lambda }_R}{hc}$

For violet light, $n_V=\frac{Pt{\lambda }_V}{hc}$

$\therefore \frac{n_R}{n_V}=\frac{{\lambda }_R}{{\lambda }_V}$

As ${\lambda }_R>{\lambda }_V$

So, $n_R>n_V$