Chemistry help! Pressure constant question- not covered in my textbook

I've been working on this question for about an hour and can't figure out what I'm doing wrong. If anyone could help me, or even tell me what to do to get the answer, I would really appreciate that. The textbook my university gave me for this chemistry course is useless and doesn't include anything about what I need to know in order to complete the question. I've looked at youtube videos, which have helped me somewhat but I'm still confused about what to do.

Pure NOCl gas was heated at 240 deg. celcius in a 1.00L container. At equilibrium, the total pressure was 1.20atm and the partial pressure of NOCl was 0.7atm.

2NOCl(g) <----> 2NO(g) + Cl2(g)

b) Calculate the equilibrium pressures of NO9g) and Cl(g) in the system.


I know that I have to use the Kp equation to get the answer, but I'm not sure how. Any help would really be appreciated

I don't think you need Kp or else it would have to be given.
2NOCl(g) <----> 2NO(g) + Cl2(g)
0.7 atm
Pt = Pnocl + Pcl2 + Pno
1.20 = 0.70 + Pcl2 + Pno
Pcl2 + Pno = 0.50 atm: since there are 3 moles of gaseous products, 0.50/3 = 0.17
Pcl2 = 0.17 atm, Pno = 0.33 atm.