Question

What are the dimensions of a rectangle with a perimeter of 70 and a length to width ratio of 4 to 5?

Answer 1

hello :
let : x the length and y the width
the perimeter is : 2(x+y)
2(x+y) = 70 and : x/y =4/5
x+y = 35 ......(1)
x = (4/5)y ... (2)
subsct in : (1)
(4/5)y +y = 35
4y+5y = 175
9y = 175
y = 175/9
in (2) : x = (4/5)(175/9) = 140/9