Quadratic Equation Problem: Week 2 Day 2 Practice

GRE Quant Problem Solving
1

For 52.00 timed problem, a ractangular rug covers half a ractangular floor that is 9 feet wide and 12 feet long. If the dimensions of the rug are in the same ratio as those of the floor, how many feet long is the rug?

For this problem, WxL=54 for the rug, then can’t we write using ratio, 3x:4x = 7x and 7x = 54, and x = 54/7

then lenght, 4x = 4 x 54/7, I have watched the class, know it doesn’t work but I am not understanding why is it not working.

Explanation regarding the problem would be much appreciated, and how we can solve it using ration would also be appreciated, thanks.

2

You can write l:w = 4:3
l * w = 4x * 3x = 12x^2
12x^2 = 54
x^2 = 54/12 = 4.5
x = \sqrt{4.5}
Length = 4x ~~ 8.5

3

Thanks, understood what was the problem.