| Exam Board | Edexcel |
|---|---|
| Module | C1 (Core Mathematics 1) |
| Marks | 8 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Arithmetic Sequences and Series |
| Type | Real-world AP: find term or total |
| Difficulty | Moderate -0.8 This is a straightforward arithmetic sequence question requiring direct application of standard formulas. Part (a) involves simple substitution into the nth term formula, part (b) uses the sum formula with given values, and part (c) requires solving a quadratic inequality—all routine C1 techniques with no conceptual challenges or novel problem-solving required. |
| Spec | 1.04h Arithmetic sequences: nth term and sum formulae |
In the first month after opening, a mobile phone shop sold 280 phones. A model for future trading assumes that sales will increase by $x$ phones per month for the next 35 months, so that $(280 + x)$ phones will be sold in the second month, $(280 + 2x)$ in the third month, and so on.
Using this model with $x = 5$, calculate
\begin{enumerate}[label=(\alph*)]
\item \begin{enumerate}[label=(\roman*)]
\item the number of phones sold in the 36th month,
[2]
\item the total number of phones sold over the 36 months.
[2]
\end{enumerate}
\end{enumerate}
The shop sets a sales target of 17000 phones to be sold over the 36 months.
Using the same model,
\begin{enumerate}[label=(\alph*)]
\setcounter{enumi}{1}
\item find the least value of $x$ required to achieve this target.
[4]
\end{enumerate}
\hfill \mbox{\textit{Edexcel C1 Q4 [8]}}