math
posted by Brayden .
In Harry's attic there are three spider webs. The first web is twice as large as the second web. The third web is 3 inches larger than the first web. The combined width of the three webs is 1 foot and 6 inches.
Aunt is stumped again!

2nd web = x in,
1st web = 2x in,
3rd web = (2x + 3) in.
x + 2x + (2x + 3) = 18 in,
5x + 3 = 18,
5x = 18  3,
5x = 15,
x = 15 / 5 = 3 in,
2x = 2 * 3 = 6 in,
2x + 3 = 2*3 + 3 = 6 + 3 = 9 in.