Saved Bookmarks
| 1. |
Find the 31st term of an AP whose 11th term is 38 and the 16th term |
|
Answer» 178Step-by-step explanation:Given that, a11=38 a16=73 We KNOW that,an=a+(n−1)da11=a+(11−1)d38=a+10d ... (i)Similarly,a16=a+(16−1)d73=a+15d ... (II)On subtracting (i) from (ii), we get35=5d∴d=7From equation (i),38=a+(10)(7)⇒38−70=a∴a=−32Now a31=a+(31−1)d=−32+30(7)=−32+210=178Hence, 31ST term is 178 |
|