The density of a gas is 1.43 g L^-1 at STP. Its density at 17 ^oC and 700 Torr will be 

${\mathrm{d}}_{\mathrm{A}}=1.43\mathrm{g}/\mathrm{L}$ at $STP$

 $\begin{array}{l}\mathrm{T}={17}^{\circ }\mathrm{C}=273+17=290\mathrm{K}\\ \mathrm{P}=700\text{ torr }=\frac{700}{760}\mathrm{atm}\end{array}$

We have  $\mathrm{PM}=\mathrm{dRT}$ 

$\Rightarrow \mathrm{M}=\frac{\mathrm{dRT}}{\mathrm{p}}=$ will remain same 

$\begin{array}{r}\Rightarrow \frac{{\mathrm{d}}_{1}R{\mathrm{T}}_1}{{\mathrm{P}}_1}=\frac{{\mathrm{d}}_2{\mathrm{RT}}_2}{{\mathrm{P}}_2}\Rightarrow {\mathrm{d}}_2={\mathrm{d}}_1\cdot \frac{{\mathrm{P}}_2}{{\mathrm{P}}_1}\cdot \frac{{\mathrm{T}}_1}{{\mathrm{T}}_2}\\ {\mathrm{d}}_2=1.43\mathrm{g}/\text{ lit. }\frac{700}{760}\times \frac{273}{290}=1.24\mathrm{g}/\text{ lit }\end{array}$