A person decides to save money by depositing ₹100 in the first week of the year. Every following week, he increases his deposit by ₹20. How much money will he have saved at the end of 20 weeks?
एक व्यक्ति वर्ष के पहले सप्ताह में ₹100 जमा करके पैसे बचाने का फ़ैसला करता है। हर अगले सप्ताह वह अपनी जमा राशि में ₹20 की वृद्धि करता है। 20 सप्ताह के अंत में उसके पास कितने पैसे बचेंगे?
Answer और ExplanationAnswer and explanation
Answer: (C) ₹5800
हर हफ़्ते की जमा राशि: ₹100, ₹120, ₹140, … — एक AP।
a = 100, d = 20, n = 20
S20 = n2[2a + (n − 1)d] = 202 × [200 + 19 × 20]
= 10 × (200 + 380) = 10 × 580 = 5800
✓
20 हफ़्तों के अंत तक उसके पास ₹5800 बचेंगे।
Weekly deposits: ₹100, ₹120, ₹140, … — an AP.
a = 100, d = 20, n = 20
S20 = n2[2a + (n − 1)d] = 202 × [200 + 19 × 20]
= 10 × (200 + 380) = 10 × 580 = 5800
✓
At the end of 20 weeks he will have saved ₹5800.
SMART APPROACH
आखिरी हफ़्ते की जमा = 100 + 19 × 20 = ₹480। कुल = 20 × 100 + 4802 = 20 × 290 = ₹5800।
Last week's deposit = 100 + 19 × 20 = ₹480. Total = 20 × 100 + 4802 = 20 × 290 = ₹5800.
Source: DP AWO/TPO · 21 Jan 2026 · Shift 2। Solution: Prashant Sir, Vijayastra।Source: DP AWO/TPO · 21 Jan 2026 · Shift 2. Solution by Prashant Sir, from Vijayastra.