A rug is to fit in a room so that a border of even width is left on all four sides. If the room is 16 feet by 25 feet and the area of the rug is 220 square feet, how wide will the border : Let x = the width of the border around the rug then (25-2x) by (16-2x) the dimensions of the rug : The area equation (25-2x)*(16-2x) = 220 sq/ft FOIL 400 - 50x - 32x + 4x^2 = 220 : Arrange as a quadratic equation 4x^2 - 82x + 400 - 220 = 0 : 4x^2 - 82x + 180 = 0
Simplify, divide by 2 2x^2 - 41x + 90 = 0 Factor (2x - 5)(x - 18) = 0 Two solutions 2x = 5 x = 2.5 ft and x = 18 ft, obviously this not the solution ; Border will be 2.5 ft : : Check this by finding the dimension of the rug, and then the area (25 - 2(2.5))*(16 - 2(2.5)) = (25 - 5) * (16 - 5) = 20 * 11 = 220
3/4 of an hour is 45 minutes. So they spent 3 hours and 45 minutes at the beach. They arrived at 10:30 so just add 3 hours and 45 minutes to their arrival time and you get 2:15pm. They left at 2:15pm
