Given K = 3.50 at 458C for the reaction A(g) +

Given K = 3.50 at 458C for the reaction
A(g) + B(g) ⇌ C(g)
and K = 7.10 at 458C for the reaction
2A(g) + D(g) ⇌ C(g)
what is the value of K at the same temperature for the reaction
C(g) + D(g) ⇌ 2B(g)
What is the value of Kp at 458C for the reaction? Starting with 1.50 atm partial pressures of both C and D, what is the mole fraction of B once equilibrium is reached?