Answer
$9200K; No$
Work Step by Step
We can find the required temperature as follows:
$T=\frac{f_{peak}}{5.88\times 10^{10}S^{-1}K^{-1}}$
$T=\frac{5.4\times 10^{14}Hz}{5.88\times 10^{10}S^{-1}K^{-1}}$
$T=9200K$
No, the firefly radiation is not well approximated by black body radiation because at a temperature of 9200K, the firefly will be completely destroyed.
