Verified Solution • 2025–26 Session moderate

QJEEM24Ma011c: JEE Main 2024 Mathematics - Class 11 JEEM24Ma011c Solution

 The 20th  term from the end of the progression 20,1914,1812,1734,…,−12914 is : \text { The } 20^{\text {th }} \text { term from the end of the progression } 20,19 \frac{1}{4}, 18 \frac{1}{2}, 17 \frac{3}{4}, \ldots,-129 \frac{1}{4} \text { is : }

Multiple Choice Options

  • A −115-115
  • B −100-100
  • C −110-110
  • D −118-118

Step-by-Step Verified Solution

20,1914,1812,1734,……,−1291420,19 \frac{1}{4}, 18 \frac{1}{2}, 17 \frac{3}{4}, \ldots \ldots,-129 \frac{1}{4}

This is A.P. with common difference

amp;d1=−1+14=−34amp;−12914,…………...1914,20\begin{aligned}& d_1=-1+\frac{1}{4}=-\frac{3}{4} \\& -129 \frac{1}{4}, \ldots \ldots \ldots \ldots . . .19 \frac{1}{4}, 20\end{aligned}

This is also A.P. a=−12914\mathrm{a}=-129 \frac{1}{4} and d=34\mathrm{d}=\frac{3}{4}

Required term ==

amp;−12914+(20−1)(34)amp;=−129−14+15−34=−115\begin{aligned}& -129 \frac{1}{4}+(20-1)\left(\frac{3}{4}\right) \\& =-129-\frac{1}{4}+15-\frac{3}{4}=-115\end{aligned}

Related Learning Resources & Exam Preparation