The temperature of a gas if its pressure is double and volume is decreased by 15% at 7 5 °C is

As specified by the IUPAC since 1982, one mole of an ideal gas has a volume of 22.710947(13) litres at standard conditions of temperature and pressure (273.15 K and precisely${10}^5$ Pa)

We have $\frac{pV}{348 \mathrm{K}}=\frac{\left(2p\right)(0.85 V)}{T}$ This gives

$T=\left(2\right) \left(0.85\right) (348 \mathrm{K})=591.6 \mathrm{K}\Rightarrow t=(591.6-273{)}^{\circ }\mathrm{C}={318.6}^{\circ }\mathrm{C}$