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| 1. |
Find the 19th term from the last term of the AP: 3,8,13,....,253. |
| Answer» a = 3, d = 5Now, 253 = a + (n + 1) d⇒ 253 = 3 + (n -1) x 5⇒ 253 = 3 + 5n – 5 = – 2⇒ 5n = 253 + 2 = 255⇒ n = 255/5 = 51Therefore, 19th term from the last term = 51 – 18 = 33a33 = a + 32d= 3 + 32 x 5= 3 + 160 = 163Thus, required term is 163 | |