I have to find the area of this trapezoid

Germaine walks at the rate of 10 feet every five seconds while nolan walks at the rate of 15 feet every five seconds. if germaine has a head start of 25 feet, how many seconds will they be at the same spot?

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Mrs. avila is buying a wallpaper border to go on all of her kitchen walls. she wants to buy 5 extra feet of wallpaper border than she needs to be sure she has enough. she buys 55.5 feet of the border. the store owner selling the border uses the width of mrs. avila's kitchen to determine that the length of her kitchen must be 14.5 feet.