Algebra 1 homework help please!?

Can someone please explain how to solve this? I would really appreciate any help! Here is the question:



A landscaper is designing a rectangular garden for an office complex. There will be a concrete walkway on 3 sides of the garden. The width of the garden will be 24 ft, and the length will be 42 ft. The width of the longer portion of the walkway will be 3 ft. The concrete will cost $20 per square yard, and the builders have told the landscaper that she can spend $820 on the concrete. How wide should the 2 remaining sides be?



Thanks!

Algebra 1 homework help please!?
The length of the longer walk is 42 ft = 42 divided by 3 = 14 yds.



It is 3 ft wide therefore the length of the other 2 walks =

24ft. - 3ft. = 21ft. each

2 walks = 2 X 21ft. = 42 ft or 14 yards

the cost is $20 per sq. yd.

and the total cost = $820.



Let x = the width of the 2 remaining sides.



Then 14xsq. yds is the area of those sides

and 1 x 14 = 14 sq. yds is the area of the longer side.

therefore 14x + 14 is the total area of the walks



NOW:

20(14x + 14) = $820.

280x + 280 = 820.

280x = 820 - 280

280x = 540

x = 540 divided by 280

x = 1.9285714 yards

OR 1.9285714 X 3 = 5.7857142 ft. or 5ft. 9.45 inches