Sum of the first twenty terms of an ap is -240 and its first term is 7. Find it\'s 24th term

Sum of the first twenty terms of an ap is -240 and its first term is 7

1.	Sum of the first twenty terms of an ap is -240 and its first term is 7. Find it\'s 24th term
Answer» Given : Sum of 20 terms of an AP =−240 and First term 7Sum of first n terms of an AP is given as S= 2n\u200b [2a+(n−1)d]n=20,S=−240,a=7⇒−240= 220\u200b [2×7+(20−1)d]⇒−240=10[14+19d]⇒−240=140+190d⇒−190d=140+240⇒−190d=380⇒d= −190380\u200b =−2n th term of an AP =a n\u200b =a+(n−1)d⇒a 24\u200b =7+(24−1)(−2)⇒a 24\u200b =7−46⇒a 24\u200b =−39