I think it’s c but don’t go with me see if others answer with a different answer :)
Answer:
Option 3 is correct that is 
Step-by-step explanation:
We have general formula for sum of cube which is

Here, we have a=s and b=6
on substituting the values in the formula we will get

After simplification we will get

After rearranging the terms we will get
which exactly matches option 3 in the given options.
Therefore, option 3 is correct that is 
2(3x +x)=30
8x = 30
x =3.75 = width
3x = 11.25 = length
Answer:
2nd one (14)
Step-by-step explanation:
525+50m=1225 take 525 from both sides
50m=700 divide 50 from both sides
m=14
If will take 14 months to save up the money.