This is a real-world application of arithmetic sequences. The number of seats in each row forms an arithmetic sequence. Given: a = 15 (first row), d = 2 (each row has 2 more), n = 20 (total rows). We need to find the sum of all seats. Using \(S_n = \frac{n}{2}[2a + (n-1)d]\): \(S_{20} = \frac{20}{2}[2(15) + (20-1)(2)]\). Simplify: \(S_{20} = 10[30 + 19(2)]\). \(S_{20} = 10[30 + 38]\). \(S_{20} = 10 \times 68 = 680\). The theater has 680 seats in total. Understanding: Row 1 has 15 seats, Row 2 has 17, Row 3 has 19, ..., Row 20 has \(T_{20} = 15 + 19(2) = 53\) seats. ECZ Paper 2 frequently includes such practical applications. Other contexts include: stadium seating, stacking patterns, saving money progressively, or production increases. These word problems test whether you can translate real situations into mathematical models. Always identify a (first term), d (common difference), and n (number of terms) from the context.

Break down complex topics into smaller, manageable chunks for easier recall.

Zambia

• Dickson Tembo – 1 pts

• Mid-point of A Line
• Equation of a Straight Line
• Parallel and Perpendicular Lines
• Area of Rectilinear Figures
• Distance of A Straight Line