Jeff and Sargon are saving money to go on a road trip. After looking at all the costs, they determine they need at least $2050 to go on the trip. Jeff shovels snow from driveways and Sargon salts the sidewalks to raise money. Jeff charges $15 each time he shovels a driveway and Sargon charges $10 each time he salts a sidewalk. The number of sidewalks that Sargon has scheduled is no more than three times the number of driveways Jeff has scheduled to shovel. Sargon plans to salt at least 35 sidewalks through the winter season. Write a set of constraints to model the problem, with x representing the number of driveways shoveled and y representing the number of sidewalks salted.