Answer:
Here is the ans ...hope it helps:)
She washed 30 plates from 7:30 to 7:35.....so she washed 30 plates in 5 minutes.....30/5 = 6 plates per minute
so if she started washing plates at 7:15 and ended at 7:38...how many plates did she wash....
from 7:15 to 7:38 is 23 minutes...and if she can wash 6 plates per minute, then in 23 minutes, she can wash (23 * 6) = 138 plates <==
the equation...
y = -6x + b...with b being the number of plates she started with and x being the number of minutes and y being the plates she has left to wash...I am not 100% sure on this equation...I am so sorry
width (w) = w
Length (L) = 3w + 4
Area (A) = L x w
25 = (3w + 4)w
25 = 3w² + 4w
0 = 3w² + 4w - 25
w = 
w ≈ 2.3, w ≈ -3.6 (width cannot be negative!)
w ≈ 2.3
Length (L) = 3w + 4 = 3(2.3) + 4 = 6.9 + 4 = 10.9
Answer: width=2.3, Length=10.9