2021 · Q45
A person saves Rs. 1000 more than he did the previous year. If he saves Rs. 2000 in the first year, in how many years will he save Rs. 170000 ?
Elementary MathematicsAlgebra
- A16 years
- B17 years
- C18 years
- D19 years
Explanation
Yearly savings form an AP: 2000, 3000, 4000, …. The sum of n terms is n/2·[4000 + (n−1)·1000] = 170000, i.e. n(n+3) = 340. Solving n² + 3n − 340 = 0 gives (n+20)(n−17) = 0, so n = 17. This is option (b).