Kilo = 1,000
Hecto = 100
Deca = 10
Base (unit) = 1
Deci = 0.1
Centi = 0.01
Milli = 0.001
X stands for the score of her first test
Y stands for the score of her second test
Let the width of the rectangle be 'w'
According to the question length of the rectangle (l) is three feet more than twice it's width;
l = (2w + 3) ft
Perimeter of rectangle = 78 ft
Formula of perimeter of rectangle = 2(Length + Width)
So,
Width of the rectangle (w) = 12 ft