If you are splitting the rent over 3 person, then their ratios will be unknown at x, x, and x + 50
Adding, we have 3x + 50 = 1525 or 3x = 1475 and x = 491.67
So, 2 roomates will pay $491.67 & the roommate with the big room will pay $ 541.67
Adding the three numbers, the total is $1525.01 so you can give the roommate with the big bed a break by asking for $541.66 ! :)