Update

Muft Shiksha™ एक 100% Free Education Portal है 🇮🇳, जिसका उद्देश्य Class 9–12 के हर विद्यार्थी तक High-Quality Education को पूरी तरह मुफ्त पहुँचाना है। 🇮🇳 हम मानते हैं कि अच्छी शिक्षा किसी student की आर्थिक स्थिति पर निर्भर नहीं होनी चाहिए। 🇮🇳 हर विद्यार्थी को वही Quality Study Material, MCQs, Quizzes, Exam Preparation, Concept-Based Learning और Bilingual Support मिलना चाहिए, जो आमतौर पर महंगी Coaching या Premium Platforms में मिलता है। Muft Shiksha™ 🇮🇳 इसी सोच के साथ बनाया गया है

Subjects
0 reads0 ratings0 helpful

If \(S_n=\frac{n}{2}(a+l)\), \(a=14\), \(l=84\), and \(n=15\), find the sum.

Answer and explanation

Correct answer: 735

Here \(a=14\), \(l=84\), and \(n=15\). Therefore, \(S_{15}=\frac{15}{2}(14+84)=\frac{15}{2}\times98=15\times49=735\). Hence, 735 is correct. Getting 745 would result from an error in addition or multiplication. Exam tip: add \(a+l\) first and simplify by 2 when the sum is even.

Related tags

Arithmetic ProgressionSum Of ApFirst TermLast TermClass 10 MathematicsFinding The Sum Of The First $N$ Terms Of An ApFinding The Sum Of The First N Terms Of An ApArithmetic Progressions (Ap)

Was this question useful?

No ratings yetWrite a review / Rate this question

Student Reviews

No published reviews yet.

Add Muft Shiksha to your Home Screen

In Safari, tap Share, then Add to Home Screen.