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| 1. |
7th and 19th terms of an A.P. are respectively 148 and 100. Which term of A.P. will be zero |
| Answer» <html><body><p><strong>Answer:</strong></p><p>Let a and d be the first <a href="https://interviewquestions.tuteehub.com/tag/term-1241851" style="font-weight:bold;" target="_blank" title="Click to know more about TERM">TERM</a> and the <a href="https://interviewquestions.tuteehub.com/tag/common-923599" style="font-weight:bold;" target="_blank" title="Click to know more about COMMON">COMMON</a> <a href="https://interviewquestions.tuteehub.com/tag/difference-951394" style="font-weight:bold;" target="_blank" title="Click to know more about DIFFERENCE">DIFFERENCE</a> of the given <a href="https://interviewquestions.tuteehub.com/tag/ap-380277" style="font-weight:bold;" target="_blank" title="Click to know more about AP">AP</a> <a href="https://interviewquestions.tuteehub.com/tag/respectively-1186938" style="font-weight:bold;" target="_blank" title="Click to know more about RESPECTIVELY">RESPECTIVELY</a>. Then,</p><p>a19=52⇒a+18d=52 ...(1)</p><p>a38=148⇒a+37d=148 ...(2)</p><p>On subtracting (1) from (2), we get</p><p>19d=96⇒d=1996</p><p></p><p>Putting d=1996 in (1), we get</p><p></p><p>a=52−18×1996=19−740</p><p></p><p>Now, S56=256[2a+(56−1)d]</p><p></p><p>∴S56=28[193800]=5600</p><p></p><p></p><p>This is your Answer </p><p></p><p></p></body></html> | |