Question

The system H2(g) + I2(g) ⇌ 2HI(g)

is at equilibrium at a fixed temperature with a partial pressure of H2 of 0.200 atm, a partial pressure of I2 of 0.200 atm, and a partial pressure of HI of 0.100 atm. An additional 0.26 atm pressure of HI is admitted to the container, and it is allowed to come to equilibrium again. What is the new partial pressure of HI?