Question

How many blocks will he have used in total ?

Answer 1

First, let's calculate the amount of blocks used in each tower:

First: x² + 2x + 3

Second: 2(x² + 2x + 3) + 3 = 2x² + 4x + 9

Third: 2(2x² + 4x + 9) + 3 = 4x² + 8x + 21

Fourth: 2(4x² + 8x + 21) + 3 = 8x² + 16x + 45

Fifth: 2(8x² + 16x + 45) + 3 = 16x² + 32x + 93

Now, adding all the polynomials, we have the total amount of blocks used:

`\begin{gathered} (1+2+4+8+16)x^2+(2+4+8+16+32)x+(3+9+21+45+93)\\ \\ =31x^2+62x+171 \end{gathered}`

Correct option: D.