Answer:
D. He forgot to subtract the area of the base from the total surface area of the cube.
Step-by-step explanation:
He is only spray washing the *exterior* of the building; the base is not exposed so it will not be spray washed, which means Richard can use less water.
Hope this helps. :)
Answer:
C
Step-by-step explanation:
Educated guess
You should start with an equation.

The 'x' represents the week.
so now, we have to subtract 125 from the total amount which is 245.

now we have

to find 'x', we must divide 15 on each side

we are now left with

that means Sierra will have 8 weeks until she has enough money to buy the bike