Mohit bought a shirt for Rs 1337.50 including VAT at 7%.

​​Let the original price of the shirt be Rs x.

VAT = 7% of Rs x

$\therefore$ Price including VAT $=$ Rs. $\left(x+\frac{7 x}{100}\right)$

$=$ Rs. $\frac{107 x}{100}$

Now, $\frac{107 x}{100}=1337.50$

$\Rightarrow x=\operatorname{Rs}\left(1337.50 \times \frac{100}{107}\right)$

= 1250

Hence, the original price of the shirt is Rs 1,250.