SSC GD Constable previous year question
What is the value of 2/(1×3) + 2/(3×5) + 2/(5×7) + ..... + 2/(45×47)?
Asked in SSC GD Constable 2024: 24 Feb 2024 Shift 3 · Quantitative Aptitude
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Correct answer: (B) 46/47
The series telescopes: 2/((2k−1)(2k+1)) = 1/(2k−1)−1/(2k+1). From k=1 to 23 (since 45=2×23−1, 47=2×23+1), the sum is 1−1/47 = 46/47.
हिंदी में प्रश्न
2/(1×3) + 2/(3×5) + 2/(5×7) + ..... + 2/(45×47) का मान कितना है?
उत्तर जाँचने के लिए किसी विकल्प पर टैप करें।
उत्तर और व्याख्या देखें
सही उत्तर: (B) 47/48
The series telescopes: 2/((2k−1)(2k+1)) = 1/(2k−1)−1/(2k+1). From k=1 to 23 (since 45=2×23−1, 47=2×23+1), the sum is 1−1/47 = 46/47.
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