Problema Solution
A rectangle has perimeter 18. If each side of the rectangle is doubled, the perimeter of the new rectangle is 36. What were the dimensions of the original rectangle?
Answer provided by our tutors
Let
x and y the dimensions of the original rectangle, x>0, y>0
2x and 2y the dimensions of the new rectangle with double sides
2(x + y) = 18
2(2x + 2y) = 36
2(x + y) = 18 divide both sides by 2
x + y = 9
y = 9 - x
9 - x > 0
x < 9
The dimensions of the original rectangle are: x and 9 - x, where x is a number from the interval (0, 9).