Time required to build a pyramid If $45$ people can built $1/2$ of a pyramid in $288$ days, how many days would it take $65$ people to build the next $1/6$ the pyramid, rounded to nearest integer, assuming each person works at the same constant rate? Question: what the term "next $1/6$ the pyramid" mean? is it, $1/6$ of the $1/2$ of the pyramid, or $1/6$ of the full pyramid?

Each person does $\;\frac{\frac12}{45}=\frac1{90}\;$ of a pyramid in $288$ days, which means each persons does $\;\frac{\frac1{90}}{288}=\frac1{25,920}\;$ of a pyramid in one day.

Thus, $\;65\;$ persons do $\;65\cdot\frac1{25,920}=\frac{13}{5184}\;$ of the pyramid every day, so if it will take them $\;k\;$ days to complete one sixth of the pyramid:

$$\frac{13k}{5,184}=\frac16\implies k=\frac{5,184}{78}=66.46\cong66$$