Following PV=nRT, we need to do a few things first. 1. We need to convert Celsius to kelvin by adding 273.15 so 25 C becomes 298.15 K and 52 C becomes 325.15 K. Using this we now move on to our universal gas constant R in PV = nRT which is 0.082057 (L*atm*K-1*mol-1) the units are important because we want only atm left. For the case of simplicity I will assume n is 1 mol. We then solve for volume with the known pressure,
V = (nRT)/P = (1*.082057*298.15)/3 = 8.15 Liters (I can't fit in the other units for the R const, temperature and Pressure) using this constant volume we then resolve for pressure using the new temperature of 325.15 K
P = (nRT)/V = (1*0.082057*325.15)/(8.15) = 3.27 atm which is our final answer. The main thing to follow is the solving for your unknown and the fact that the R gas constant will cancel out unwanted units if done correctly.