Explanation: the multiplicative rate is the ratio of the values y(k)/y(k+1) (with k being the index). This ratio must be the same for the function to be exponential. We can take y(2)/y(1) = 4/6 = 2/3.
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.
