| Exam Board | WJEC |
|---|---|
| Module | Unit 3 (Unit 3) |
| Year | 2023 |
| Session | June |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Geometric Sequences and Series |
| Type | Compound growth applications |
| Difficulty | Moderate -0.8 This is a straightforward geometric progression question requiring standard formulas. Part (a) uses the sum of a GP formula with clear parameters (a=32, r=0.9, n=10), and part (b) recognizes the sum to infinity exists since |r|<1. Both parts are routine applications of memorized formulas with no problem-solving insight required, making it easier than average but not trivial due to the multi-step calculation. |
| Spec | 1.04i Geometric sequences: nth term and finite series sum1.04j Sum to infinity: convergent geometric series |r|<1 |
A tree is 80 cm in height when it is planted. In the first year, the tree grows in height by 32 cm. In each subsequent year, the tree grows in height by 90% of the growth of the previous year.
\begin{enumerate}[label=(\alph*)]
\item Find the height of the tree 10 years after it was planted. [4]
\item Determine the maximum height of the tree. [2]
\end{enumerate}
\hfill \mbox{\textit{WJEC Unit 3 2023 Q5 [6]}}