Vardaan Learning Institute
Answer Key: Arithmetic Progressions PYQ
Class: 10 (CBSE)
Subject: Mathematics
Chapter: 05
BOARD EXAM 2025 (Set 30/6/3)
Q38 (Case Study). A school prepared an eight lane running
track. The length of innermost lane is 400 m and each subsequent lane is 7.6 m longer. Answer:
(i) Length of 6th lane? [1 Mark]
(ii) How long is 8th lane than 4th lane? [1 Mark]
(iii) (a) Total distance in first six lanes. OR (b) Total distance from lane 4 to lane 8. [2 Marks]
AP: \(a = 400, d = 7.6\).
(i) \(a_6 = 400 + 5(7.6) = 438\) m.
(ii) \(a_8 - a_4 = 4d = 30.4\) m.
(iii)(a) \(S_6 = 3[800 + 38] = 2514\) m.
(iii)(b) Sum of lanes 4-8: \(\frac{5}{2}[422.8 + 453.2] = 2190\) m.
(i) \(a_6 = 400 + 5(7.6) = 438\) m.
(ii) \(a_8 - a_4 = 4d = 30.4\) m.
(iii)(a) \(S_6 = 3[800 + 38] = 2514\) m.
(iii)(b) Sum of lanes 4-8: \(\frac{5}{2}[422.8 + 453.2] = 2190\) m.