Problema Solution
A poster is 25 cm taller than it is wide. It is mounted on a piece of cardboard so that there is a 5 cm border on all sides. If the area of the border alone is 1350cm^2, what are the dimensions of the poster?
Answer provided by our tutors
let
h = the height of the poster
w = the width of the poster
a poster is 25 cm taller than it is wide
h = 25 + w
the area of the border alone is = the total area (together with the border) - the poster area
1350 = (h + 5)(w + 5) - h*w
(h + 5)(w + 5) - h*w - 1350 = 0
plug h = 25 + w into the last equation
(25 + w + 5)(w + 5) - (25 + w)w - 1350 = 0
by solving we find
w = 120 cm
h = 120 + 25 = 145 cm
click here to see the step by step solution of the equation
the height of the poster is 145 cm
the width of the poster is 25 cm.