As said in the question, P = 2w + 2l Also from the question, we know that w = 1 + 1/4l because it said that the width of the classroom is 1metre more than 1/4 of its length.
Substitute w =1 + 1/4l into 2w from P = 2w + 2l So, P = 2(1 + 1/4l) +2l Multiply (1 + 1/4l) by 2 So, since P =24 24 = 2 + 2/4l + 2l
Multiply all the units by 4l to remove the denominator which is 4l So, 24 * 4l =(2 * 4l)+ (2/4l * 4l)+(2l * 4l) 96l = 8l + 2 + 8l²
