`A(s)hArrH_(2)S(g)+B(g)` At eq., pressure = 18 atm
`C(s)hArrH_(2)S(g)+D(g)` At eq., pressure = 36 atm
Calculation
total pressure at new equilibrium when both the solids are heated simultaneously

Explanation

`A(s)hArrunderset(x+y x)( H_(2)S(g))+B(g),K_(p_(1))=(9)^(2)=81`
`C(s)hArrunderset(x+y y)(H_(2)S(g))+D(g),K_(p_(2))=(18)^(2)=324`
total pressure `= x + y + x + y = 2 (x + y)`
`K_(p_(1))+k_(p_(2))=(x+y)^(2)rArrx+y=sqrt(k_(p_(1))+k_(p_(2)))`
`rArr` total pressure `= 2 (x + y) = 2sqrt(K_(p_(1))+k_(p_(2)))`
`=2sqrt(81+324)=2sqrt(405)` atm