Fewpal
+2 votes
7.4k views
in Mathematics by (127k points)
edited by
Find the 20th term from the last term of the AP : 3, 8, 13, . . ., 253.

1 Answer

+2 votes
by (25.9k points)
selected by
 
Best answer

Solution: a = 3, d = 5

Now, 253 = a + (n + 1) d

⇒ 253 = 3 + (n -1) x 5

⇒ 253 = 3 + 5n – 5 = – 2

⇒ 5n = 253 + 2 = 255

⇒ n = 255/5 = 51

Therefore, 20th term from the last term = 51 – 19 = 32

a32 = a + 31d

= 3 + 31 x 5

= 3 + 155 = 158

Thus, required term is 158

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...