Moderate -0.8 This is a straightforward application of the binomial theorem requiring students to identify the correct term, write out the binomial coefficient formula, set it equal to the given value, and solve a simple equation for p. It's more routine than average with minimal problem-solving required.
The coefficient of $x^3$ in the expansion of $(1 - px)^5$ is $-2160$. Find the value of the constant $p$. [3]
\hfill \mbox{\textit{CAIE P1 2019 Q1 [3]}}